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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.
191

Transformation of Phosphorus in Highway Runoff Management Systems

Pearce, David B. 01 January 1984 (has links) (PDF)
The operation and maintenance of highways contributes a variety of pollutants to surface and subsurface waters. Solids, heavy metals, nutrients, oil and grease, pesticides and bacteria can all be associated with highway runoff. Although the full extent of the effect of all these runoff constituents upon the quality of surrounding waters is not well defined, this study will mainly concentrate on nutrient contaminants (essentially phosphorus). The last decade has seen increasing efforts in research and development to abate contaminant discharges from highway runoff using a number of treatment facilities such as swale and detention/retention ponds. An evaluation of the effectiveness of these systems in removing phosphorus by physical, chemical and biological uptake is the aim of this research endeavor. This study represent the first step towards the determination of design criteria for swales and detention/retention ponds based on water quality improvement.
192

Geophysical investigations of near-surface mine sites in northern West Virginia

Fahringer, Peter E. January 1999 (has links)
Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains ix, 130 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 128-130).
193

Long-term Subsurface Drainage Effects on Soil Physical and Hydraulic Properties

Daniel T Welage (8908151) 15 June 2020 (has links)
Subsurface tile drainage is a common management practice implemented by farmers throughout the Midwest in fields that have poorly drained soils. Tile drainage has several benefits including increased productivity, reduced erosion, and increased trafficability. However, relatively little is known about the long-term change of soil properties that may occur as a result of subsurface drainage. Careful monitoring of tile drains at the long-term experimental site at the Southeast Purdue Agricultural Center led to the observation of faster drain flow than in the past, with hydrographs of the flow showing flashier peaks, suggesting that more preferential flow paths have developed over time. The overall goal of this study was to characterize possible evolution of physical and hydraulic properties of this silt loam soil after 35 years of subsurface drainage. Bulk density and water retention were measured in May of 2018 at 0-5 cm, 5-15 cm, and 15-30 cm in all plots and again in July of 2019 in the 5 m and 40 m spacings at four different horizons down to depths of approximately 100 cm, rather than set depth increments. Bulk density results from both sets of sampling show the 5 m spacing to have a significantly lower bulk density than the 40 m spacing in the top 30 cm of soil, although the difference was small. Differences in water retention among treatments were too small to be physically meaningful. Saturated hydraulic conductivity results measured by three different methods were highly variable and no differences were detected. In soils with naturally weak structure, low organic matter, and low clay content, like the soil in this study, the processes responsible for soil aggregation, structure stabilization, and lowering bulk density are inherently slow and may require longer than 35 years of subsurface drainage to produce significant changes in the physical properties measured.
194

Artificial land drainage in Manitoba: history, administration, law

Elliott, William P. 01 January 1977 (has links)
A history of the development and organization of artificial land drainage in Manitoba and the involvement of statutory authorities in land drainage is reviewed. The Department of Mines, Resources and Environmental Management Water Resources Division, conservation districts and municipal governments divide jurisdiction and responsibility over watercourses in Manitoba. The Prairie Farm Rehabilitation Administration and the Manitoba Department of Agricultural Technical Services Branch provide conditional assistance to farmers contemplating slough drainage. The Agricultural and Rural Development Agreement and the Fund for Rural Economic Development Program contain comprehensive drainage programs in Manitoba. The common and statute law concerning drainage is reviewed. Legal drainage procedures for individuals, rural municipalities, conservation districts and the Province of Manitoba are outlined. In addition, procedures for obtaining drainage assistance from the Manitoba Department of Agriculture and the Prairie Farm Rehabilitation Administration are also presented. Many statutory provisions concerning drainage in Manitoba are obscure and inconsistent. Clarification of these provisions is sorely needed before drainage law can be used as an effective tool in a wetland preservation effort.
195

Artificial land drainage in Manitoba: history, administration, law

Elliott, William P. 01 January 1977 (has links)
A history of the development and organization of artificial land drainage in Manitoba and the involvement of statutory authorities in land drainage is reviewed. The Department of Mines, Resources and Environmental Management Water Resources Division, conservation districts and municipal governments divide jurisdiction and responsibility over watercourses in Manitoba. The Prairie Farm Rehabilitation Administration and the Manitoba Department of Agricultural Technical Services Branch provide conditional assistance to farmers contemplating slough drainage. The Agricultural and Rural Development Agreement and the Fund for Rural Economic Development Program contain comprehensive drainage programs in Manitoba. The common and statute law concerning drainage is reviewed. Legal drainage procedures for individuals, rural municipalities, conservation districts and the Province of Manitoba are outlined. In addition, procedures for obtaining drainage assistance from the Manitoba Department of Agriculture and the Prairie Farm Rehabilitation Administration are also presented. Many statutory provisions concerning drainage in Manitoba are obscure and inconsistent. Clarification of these provisions is sorely needed before drainage law can be used as an effective tool in a wetland preservation effort.
196

Understanding the mechanisms of oxidation of pyritic shale in mining waste and the influence of shale properties on acid mine drainage in the Pilbara Basin

Song, Meining January 2010 (has links)
[Truncated abstract] The influence of environmental conditions and properties of pyritic shale in the mining waste from Mt. Whaleback in Western Australia, in particular the inclusions and encapsulation of pyrite on the oxidation of pyritic shale and its subsequent acid mine drainage, was studied by employing an isothermal batch reactor system and QEMSCAN technique. The experimental technique was validated by comparing the experimental results obtained in this study with the literature data. It was found that the presence of water significantly accelerates the rate of shale oxidation. Weathering of the shale samples was found to influence the O2 consumption rate. It was also found that shale properties have a major effect on the oxidation rate and thereby affect the acid generation. Static test methods (Sobek and Lawrence) were employed to test the Neutralisation Potential (NP) of more than 100 actual and composite samples including pyritic shale samples, rock samples, mineral samples, various pyrite-mineral, pyrite-shale, and pseudo-shale blends. The influence of sample properties (bulk elemental composition, and mineralogy), test technique (Sobek and Lawrence) and associated variables (acid strength and volume) on the acid neutralisation potential of the samples was studied. It was found that the Sobek method produced consistently higher NP results under comparable acid conditions to those obtained with the Lawrence method. The theoretical NP values of individual minerals were calculated based on the mineral composition combined with the acid neutralising equations and ideal chemical formula. ... To experimentally model the major mineral phases, 11 minerals were used to produce pyrite-mineral blends and pseudo-shales, whose compositions mimic those of the actual shales studied. Mineral blends were employed to evaluate and contrast their individual acid generation or neutralisation behaviour with binary and higher order interactions. Blends of pyrite with some selected shales were also employed in this study. It was found that interactions can occur between the multiple mineral components which can enhance the rate of acid generation beyond that of the individual behaviour. It was found that the products from the pre-oxidation of shales, the properties and morphology of a sample such as the surface area, encapsulation, the mineralogy and pH all play a significant role in the acid generation and neutralisation rates. However, the absolute rate of acid generation appears to be most sensitive to the components such as Fe3+, which contribute to its reaction mechanisms. This investigation has provided a scientific insight into the acid generation and neutralisation behaviour of pyritic shale in relation to its mineralogy. It was found that the relative instantaneous rates of acid generation and consumption for individual minerals can be significantly different to that of their total potentials for acid generation and neutralisation. The significantly different behaviour of the actual and pseudo shales suggests that at low pH, there may be other mechanisms underlying the net capacity and rates of shales to generate or consume acid than bulk mineralogy. These findings have significant implications to the mining industry operating in reactive grounds.
197

Characterization of Agricultural Subsurface Drainage Water Quality and Controlled Drainage in the Western Lake Erie Basin

Pease, Lindsay Anne 28 September 2016 (has links)
No description available.
198

The ecology of algal assemblages across a gradient of acid mine drainage stress on the West Coast, South Island, New Zealand

Bray, Jonathan Peter January 2007 (has links)
Physicochemical factors, algal diversity, taxonomic composition and standing crop were investigated across a broad gradient of AMD stress in streams and rivers. 52 sites were surveyed in the vicinity of Greymouth, Reefton, Westport and Blackball, on the West Coast, South Island. Seven sites in the Reefton area were sampled from April 2006 - February 2007 to establish changes over time in benthic algal communities of AMD and reference streams. Longitudinal change and ecosystem recovery were also investigated by sampling eight sites down Devils Creek, Reefton, and two of its tributaries. AMD has negative impacts on algal diversity, generally increases the dominance of certain taxa and, where metal oxide deposition or hydraulic disturbance are not great, can lead to algal proliferations. These proliferations were chlorophyte dominated, predominantly by filamentous Klebsormidium acidophilum. From the general survey a total of 15 taxa were identified from the most severely impacted sites (pH <3.6), which included both acidophiles and acidotolerant algae. Multivariate analyses strongly suggest that pH was the dominant factor controlling taxonomic occurrence of diatoms, macroalgae and the structure of the total assemblage. Other factors such as conductivity, metal oxide deposition, temperature, depth, month, geographic location and altitude were also important. Algal communities changed over time and this became more marked as AMD impact decreased. This was presumably due to AMD stressors reducing diversity, and thus the available scope for assemblage change. Longitudinal differences in assemblage structure within Devils Creek appeared to be in response to dilution of AMD in upper reaches and to changes in natural physical features such as gradient in mid and lower reaches. After a distance of 7.2 km the physicochemical effects of AMD and suspended clay inputs were minimal. At this site and at several previous sites, the assemblage exhibited a degree of recovery towards that found at unimpacted sites. A range of algae found in the broad scale-survey are potentially useful 'sensitive' indicators. These included: Heteroleibleinia purpurascens; Achnanthes oblongella; Oedogonium sp. and Spirogyra sp. In contrast: Euglena mutabilis; Navicula cincta; K. acidophilum; Microspora quadrata and Microthamnion kuetzingianum may be useful 'tolerance' indicators. These data show that AMD has a range of negative impacts on algae, and algae may be a useful tool for monitoring these impacts in West Coast streams.
199

Rational drainage design for the desert Southwest.

Lueck, Curtis Calvin. January 1989 (has links)
Drainage systems for the desert Southwest are currently designed without much consideration for the climatological or surficial conditions of the region. The "100 year" flood has become the design standard throughout the United States due to misunderstandings about requirements of the National Flood Insurance Program. The effect of larger floods is virtually ignored, seasonal variations of rainfall patterns and intensities are neglected, and hydrologic data collection is extremely limited in watersheds of the urbanizing Southwest. The laws of nature are obscured by the rules of man during the planning and design of desert drainageways. Procedures for extrapolating runoff records and estimating the magnitude of the 100-year flood, including the LP III probability density function, the NOAA Atlas, and HEC-1, have been widely adopted in the arid regions as part of local drainage regulations. Plans are normally not approved unless the basis of design complies with the regulations. Assumptions inherent in the methods are questionable and data to verify the assumptions are limited. Drainage design can be improved by using available field data and a simple method--based on the Rational Method--is developed. Benefit-cost analysis is a valuable tool for establishing project alternatives, project size, and cost/benefit allocation. An equitability index is defined for evaluating fairness, and it is combined with the benefit-cost ratio for refining and selecting project design. Estimates of flood peaks can be improved by considering channel abstractions as "negative base flow"; by recognizing the presence of the n-value paradox; by extending flood records through paleohydrologic study; by monitoring rainfall, runoff, and the effectiveness of design strategies in urban catchments; and by using more suitable rainfall estimates. Drainage design can be made more rational by also considering sediment transport; by including nonstructural design alternatives; and by evaluating a range of flood magnitudes, not just the 100-year flood. A conceptual drainage ordinance not based on the NFIP is presented.
200

AN APPLICATION OF THE PRINCIPLES OF FLOW THROUGH PARTIALLY SATURATED POROUS MEDIA TO PROBLEMS OF AGGLOMERATED HEAP LEACHING.

Kelzieh, Amer, 1959- January 1985 (has links)
No description available.

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