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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.
211

Development of an integrated approach to understanding, managing and designing strategies and recycled organics filtration treatment system to control regional heavy metal contamination of stormwater.

Seelsaen, Nida, Civil & Environmental Engineering, Faculty of Engineering, UNSW January 2007 (has links)
Urban stormwater runoff is recognised as a substantial source of heavy metal contamination, which adversely impacts on water quality of regional receiving waterways. Conventional treatment of urban runoff mostly involves a filtration system using sand to retain particulate matters. Sand provides limited sorption of dissolved metals and the inclusion of commercial sorbents to these treatment systems is not cost effective due to the concentration of dissolved metals in the runoff. Recycled organic materials are by-products or waste from industrial or agricultural operations, and could be alternative low cost sorbents for stormwater treatment systems. The use of recycled sorbents also provides added value to the waste materials and reduces landfill disposal. The research explores the application of compost, zeolite, ash, and recyclable waste in urban runoff treatment, especially for dissolved metal removal. The research combines the two aspects of experimental studies and management analysis to develop a holistic approach to heavy metal control in urban stormwater systems. Experimental results of batch sorption test show that compost is suitable for removing dissolve copper in stormwater treatment. The comparison of the different mixing ratios between compost and glass beads in column test evaluates the optimum mixing sorbent and performance over a long period for copper removal. Substance Flow Analysis (SFA) of copper has been performed in the Upper Parramatta River Catchment, Sydney to identify the sources of copper associated with runoff, effect of using waste material such as compost in urban stormwater treatment and the copper load in urban stormwater runoff. This case study shows the relationship between copper input, copper stock, sorbent type and urban stormwater quality control in the system boundary of the catchment. Different scenarios of source control are evaluated to control copper load from the different sources. Source control focusing on roads and vehicles is the most effective copper control strategy. The combination of source control and stormwater treatment reduces copper in stormwater and receiving water. The thesis applies the analysis from SFA and experimental results to derive both a regional system-wide solution with source control, and an improved design of stormwater treatment for heavy metal removal using recycled organics.
212

Identification, transport and treatment of adhered deleterious substances of stormwater in an urban catchment

Ng, Warren Heng Wan Unknown Date (has links)
This thesis develops and presents a practical, rapid and cost effective method of assessing the most efficient strategy to limit sediment and associated contaminants from entering and impacting on Auckland's waterways. Although sediment removal objectives have been defined by Auckland Regional Council's stormwater quality guidelines, the deployment of treatment systems based upon current best management practice does not ensure that these objectives will be achieved. Due to the lack of established methods for the collection and analysis of stormwater related contaminants, an elaborate sampling and analytical protocol was established to validate the results obtained. The research has been undertaken as a series of studies with specific sampling methodology described in detail at the beginning of each study. Current issues and practices relating to the local stormwater industry are also reviewed.The accumulation of metal contaminants in estuarine studies is typically considered in terms of the preferential accumulation of heavy metals in the sediment fine fraction and the accumulation of these contaminants in the bulk sediment. For these data to be considered in the context of stormwater treatment, a third factor, looking at the total mass load distribution of these contaminants within the particle ranges of sediment is introduced. This thesis proposes that a substantial amount of coarser particles are making their way into our receiving environment and that attached to them are a significant proportion of the total contaminant load. Although the contaminants on coarse particles may not be bioavailable in their original state, they undergo physical changes while in transport and once deposited the chemical and biological effects on the receiving environment will ultimately be just as detrimental.A contaminant yield assessment method is developed in which the removal efficiency of every stormwater contaminant can be accessed based on a target sediment removal range. From a cost-benefit perspective, the marginal benefit of higher contaminant removal is also discussed. Finally the framework of a contaminant-based stormwater model, incorporating provenance, nature and transport is developed to access the true nature of stormwater contamination discharged to the receiving environment. The model will generate generic particle and contaminant distributions, which may be used by policy makers to predict treatment efficiencies based on target sediment removal objectives.
213

Chemical relationships in waters and sediments of some urban streams, with particular reference to heavy metals and phosphorus

Hayes, Warwick Jay January 1996 (has links)
This thesis describes two studies of the chemistry of freshwater streams in the Sydney basin. The first was a survey of 86 waterways, sampled under low conditions. Samples were generally low in salinity, soft, of poor buffering capacity and dominated by sodium and chloride. C0-dominance by calcium, magnesium and (bi)carbonate occured in a number of particular cases. Multivariate analyses indicated three groups, separated primarily by levels of dissolved nutrients, trace metals, turbidity and colour. Groupings were associated strongly with the type of catchment. Streams in areas relatively unaffected by human influence had notable uniformity in chemistry, while those from developed catchments were varied. Heavy metal contamination was relatavely low, although a few of the samples displayed inordinately large levels of one or more metals. In such cases the more extreme measurements of phosphorus and nitrogen were also seen. The findings were consistant with occasional or localised elevation of contaminant levels. The second study invloved monitoring of three Hawkesbury Sandstone streams. Sampling of surface waters, interstial waters and sediments was performing at irregular intervals over a two year period at three stations within each site. The streams predominantly existed under low conditions and showed similar major ion chemistries to the majority of the survey samples. Levels of calcium and total carbonate, plus heavy metals and nutrients were generally higher in the urbanised creeks, comapred to the reference strema. During a heavy storm, high levels of nutrients, suspended solids and colour were detected in all surface waters at peak-flow, as well as alkaline pH, oxidising redox, and reduced conductivity, alkalinity and hardness. The sandy sediments were characterised by very low levels of organic matter and cation exchange capacity. Sequential extractions identified that the sums of secondary phase lead, zinc and copper were over nine, four and two times that of the corresponding residual, respectively. Greatest proportions of zinc and lead were associated with coatings of iron and maganese oxides, or coarse waste particles. Copper was preferentially associated with organic matter. Concentration gradients between interstitial and surface waters were rare and release of sedimentary constituents should occur from the upper-most particulates. Poor water and sediment qualities were often observed in the urban sites. Poor water quality was also seen on occassion in the reference stream. However, since poor sediment quality was not detected at those times and interstitial waters for all sites displayed high within-site variability, surface waters were considered the most reliable short-term indicator of condition for Hawkesbury Sandstone streams. Multidimensional scaling showed that all streams had distinct water and sediment chemistries. High levels of temporal and spatial variability were apparant within the urbanised sites - particularly in interstitial waters - mostly due to concentrations of heavy metals, phosphorus and suspended solids. Seasonal differences were detected, but only in terms of the level of variability between summer and winter samples.
214

Zhuji wetland city stormwater recycle /

Chen, Yuxiao. January 2007 (has links)
Thesis (M. L. A.)--University of Hong Kong, 2007. / Includes special report study entitled: Water level control technology in constructed wetland. Title proper from title frame. Also available in printed format.
215

BMP adoption in two East Tennessee watersheds

Barrowclough, Michael John, January 2006 (has links) (PDF)
Thesis (M.S.) -- University of Tennessee, Knoxville, 2006. / Title from title page screen (viewed on Feb. 7, 2007). Thesis advisor: Ernest Bazen. Vita. Includes bibliographical references.
216

Development of a cell-based stream flow routing model

Raina, Rajeev 29 August 2005 (has links)
This study presents the development of a cell-based routing model. The model developed is a two parameter hydrological routing model that uses a coarse resolution stream network to route runoff from each cell in the watershed to the outlet. The watershed is divided into a number of equal cells, which are approximated as cascade of linear reservoirs or tanks. Water is routed from a cell downstream, depending on the flow direction of the cell, using the cascade of tanks. The routing model consists of two phases, first is the overland flow routing, which is followed by the channel flow routing. In this study, the cell-to-cell stream flow routing model is applied to the Brazos River Basin to demonstrate the impact of the cascade of tanks on the flow over a simple linear reservoir method. This watershed was tested with a uniform runoff depth in absence of observed runoff data. A case study on Waller Creek in Austin, Texas with observed runoff depths and stream flow is used to demonstrate the calibration and validation of model parameters.
217

Spatial variability of snowmelt water balances in a subarctic catchment, Wolf Creek, Yukon

McCartney, Stephen Edward 22 March 2006
The intra-basin variability of snowmelt and meltwater runoff hydrology in an 8 km2 subarctic alpine tundra catchment was examined for the 2003 melt period. The catchment, Granger Creek, is within the Wolf Creek Research Basin, Yukon which is typical of mountain subarctic landscapes in north-western Canada. The study catchment was segmented into nine internally uniform zones termed Landscape Units (LUs) based on their similar hydrological, physiographic, vegetation and soil properties. Snow accumulation exhibited significant variability among the LUs, with greatest snow water equivalent in areas of tall shrub vegetation. Melt began first on southerly exposures and at lower elevations, yet average melt rates for the study period varied little among LUs with the exception of those with strong aspects. In LUs with capping organic soils, meltwater first infiltrated this surface horizon, satisfying its storage capacity and then percolated into the frozen mineral substrate. Infiltration and percolation into frozen mineral soils was restricted where melt occurred rapidly and organic soils were thin; in this case meltwater delivery rates exceeded the frozen mineral soil infiltration rate, resulting in high runoff rates. In contrast, where there were slower meltrates and thick organic soils, infiltration was unlimited and runoff was suppressed. The snow water equivalent had a large impact on runoff generation as soil storage capacity was quickly surpassed in areas of deep snow, diverting the bulk of meltwater laterally to the drainage network. A spatially distributed water balance indicated that snowmelt freshet was primarily controlled by areas with tall shrub vegetation that accumulate large quantities of snow and by alpine areas with no capping organic soils. The intra-basin water balance variability has important implications for modeling freshet in hydrological models.
218

Characteristics and climatic sensitivities of runoff from a cold-type glacier on the Tibetan Plateau

Fujita, Koji, 藤田, 耕史, Ohta, Takeshi, Ageta, Yutaka January 2007 (has links)
No description available.
219

Effect of dust event timing on glacier runoff: sensitivity analysis for a Tibetan glacier

Fujita, Koji, 藤田, 耕史 January 2007 (has links)
No description available.
220

Spatial variability of snowmelt water balances in a subarctic catchment, Wolf Creek, Yukon

McCartney, Stephen Edward 22 March 2006 (has links)
The intra-basin variability of snowmelt and meltwater runoff hydrology in an 8 km2 subarctic alpine tundra catchment was examined for the 2003 melt period. The catchment, Granger Creek, is within the Wolf Creek Research Basin, Yukon which is typical of mountain subarctic landscapes in north-western Canada. The study catchment was segmented into nine internally uniform zones termed Landscape Units (LUs) based on their similar hydrological, physiographic, vegetation and soil properties. Snow accumulation exhibited significant variability among the LUs, with greatest snow water equivalent in areas of tall shrub vegetation. Melt began first on southerly exposures and at lower elevations, yet average melt rates for the study period varied little among LUs with the exception of those with strong aspects. In LUs with capping organic soils, meltwater first infiltrated this surface horizon, satisfying its storage capacity and then percolated into the frozen mineral substrate. Infiltration and percolation into frozen mineral soils was restricted where melt occurred rapidly and organic soils were thin; in this case meltwater delivery rates exceeded the frozen mineral soil infiltration rate, resulting in high runoff rates. In contrast, where there were slower meltrates and thick organic soils, infiltration was unlimited and runoff was suppressed. The snow water equivalent had a large impact on runoff generation as soil storage capacity was quickly surpassed in areas of deep snow, diverting the bulk of meltwater laterally to the drainage network. A spatially distributed water balance indicated that snowmelt freshet was primarily controlled by areas with tall shrub vegetation that accumulate large quantities of snow and by alpine areas with no capping organic soils. The intra-basin water balance variability has important implications for modeling freshet in hydrological models.

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