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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.
111

The Influence of Geology and Other Environmental Factors on Stream Water Chemistry and Benthic Invertebrate Assemblages

Olson, John R. 01 May 2012 (has links)
Catchment geology is known to influence water chemistry, which can significantly affect both species composition and ecosystem processes in streams. However, current predictions of how stream water chemistry varies with geology are limited in both scope and precision, and we have not adequately tested the specific mechanisms by which water chemistry influences stream biota. My dissertation research goals were to (1) develop empirical models to predict natural base-flow water chemistry from catchment geology and other environmental factors, (2) extend these predictions to nutrients to establish more realistic criteria for evaluating water quality, and (3) test the hypothesis that catchment geology significantly influences the composition of stream invertebrate assemblages by restricting weak osmoregulators from streams with low total dissolved solids (TDS). To meet goal 1, I first mapped geologic chemical and physical influences by associating rock properties with geologic map units. I then used these maps and other environmental factors as predictors of electrical conductivity (EC, a measure of TDS), acid neutralization capacity, and calcium, magnesium, and sulfate concentrations. The models explained 58 – 92% of the variance in these five constituents. Rock chemistry was the best predictor of stream water chemistry, followed by temperature, precipitation and other factors. To meet goal 2, I developed empirical models predicting naturally occurring stream total nitrogen and total phosphorus concentrations. These models explained most of the spatial variation among sites in total nitrogen and phosphorus and produced better predictions than previous models. By determining upper prediction limits that incorporated model error, I demonstrated how predictions of nutrient concentrations could be used to set site-specific nutrient criteria and accounted for natural variation among sites better than regional criteria. To meet goal 3, I experimentally manipulated (high and low) EC in both stream-side and laboratory flowthrough microcosms and measured survival, growth, and emergence of 19 invertebrate taxa. Observed variation among taxa in survival between treatments predicted taxon EC optima estimated from field observations (r² = 0.60). Taxa with the greatest differences in survival between treatments also had the highest EC optima, indicating that the inability to persist in low EC likely restricts the distributions of some taxa.
112

Twentieth Century Channel Change of the Green River in Canyonlands National Park, Utah

Walker, Alexander E. 01 December 2017 (has links)
Since the early 20th century, river channels of the Colorado River basin have narrowed, decreasing available riparian and aquatic habitat. Changes are considered to be the result of three major factors: wide-spread water development, increasing hydroclimate variability and the invasion of non-native tamarisk (Tamarix spp.), altering flow regime and sediment supply. Different studies have reached different conclusions about the relative roles of flow regime, sediment supply and tamarisk in causing narrowing. I investigated channel change in the lower Green River within Canyonlands National Park to describe channel changes in the 20th century and understand the roles of shifting flow regime and changing vegetation communities on 20th century channel narrowing. The lower Green River within Canyonlands National Park has narrowed substantially since the late 1800s, resulting in narrower channel. Changes to flood magnitude, rate and timing since 1900, driven by increased water storage and diversion in the Green River basin and declines in annual precipitation, was responsible for inset floodplain formation documented in this study. I used multiple datasets to reconstruct the history of channel narrowing in the lower Green River and identify processes of floodplain formation. In the field, analyses of a floodplain trench were described to identify rate, timing and magnitude of floodplain formation. Channel and floodplain surveys were conducted to determine possible changes in bed elevation. Additionally, I analyzed existing aerial imagery, hydrologic data, and sediment transport data. I applied these techniques to determine how floodplain formation occurred at multiple spatial and temporal scales. My investigation shows that the floodplains of the contemporary lower Green River began forming in the late 1930s and continued to form in the 20th century by inset floodplain formation. During this time period, peak flow and total runoff declined due to climatic changes and human water development. Since the mid-1980s, inset floodplains continued to develop along the lower Green River since the mid-1980s, narrowing the river by an additional 9.4%. Analysis of aerial imagery shows that changes to the floodplain identified in the trench occurred throughout the 61 km of river I studied. Non-native tamarisk (Tamarix spp.) did not drive channel narrowing, though dense stands stabilized banks and likely promoted sediment deposition. Inset floodplain formation reflects changes to flooding resulting from water development and climate change. My findings have implications for the long-term management of the lower Green River and endangered endemic native fishes –particularly the Colorado pikeminnow (Ptychocheilus lucius) and the razorback sucker (Xyrauchen texanus). Collaboration with upstream stakeholders and managers is necessary to preserve elements of the flow regime that preserve channel width and limit channel narrowing.
113

From Water to Resource: A Case of Stakeholders' Involvement in Usangu Catchment, Tanzania

Timanywa, Jofta January 2009 (has links)
<p> </p><p>High pressure on water from competing users has changed the past perception of water as gift to water as a resource that requires sustainable management. Management of water resource needs active stakeholders’ involvement for its sustainability. Many organizations along with the national water policy have been calling for active stakeholders’ involvement for management of the resource.  In Usangu catchment conflicts over accessing water between farmers and pastoralists and between upstream and downstream have been common. Water allocation in the catchment has been done without involving stakeholders and adequate consideration of the rivers’ carrying capacity. This study focuses on stakeholders’ involvement in Usangu catchment. Six villages in three sub-catchments were studied and data were collected using questionnaire through face to face interview and focus group discussion. The study found that there is limited stakeholders’ involvement in Usangu catchment. In some places involvement is at basic stage, in other places there is no involvement. Interaction within stakeholders’ category was documented, while no stakeholders’ interaction between sub-catchments was discovered. Moreover, some challenges for active involvement were noted, such as lack of coordination between institutions operating in the catchment, high illiteracy rate and lack of awareness, and with lack of legislation support. The issue of limited stakeholders’ involvement in Usangu catchment is complicated, there is no single and comprehensive solution; integration of different approaches which are cross-sectoral in nature is needed for sustainable water management.</p><p> </p>
114

Modeling Soil Erosion in the Upper Green River, KY

Pricope, Narcisa 01 December 2006 (has links)
Off-site soil erosion has tremendous impacts on the present state of most river systems throughout the United States, contributing sediments to channels mainly as nonpoint pollution resulting from land-use and agricultural practices and leading to sedimentation downstream and downwind, a decrease in the transport capacity of streams, increase in the risk of flooding, filling reservoirs, and eutrophication. A primary focus in examining the problems associated with soil erosion arid ultimately in proposing control measures should be on identifying the sources of the sediment. Therefore, a model that would be able to assess soil erosion needs to start by identifying the sediment sources and delivery paths to channels, link these sediment supply processes to in-channel sediment transport and storage and ultimately to basin sediment yield. This study focuses on the Upper Green River Basin in Kentucky and is concerned with analyzing hillslope erosion rates using The Unit Stream Power Erosion and Deposition soil erosion model (Mitas and Mitasova, 1996) and GIS, and thereby estimating patterns of sediment supply to rivers in order to predict which portions of the channel network are more likely to store large amounts of fine sediments. Results indicate that much of the eroded sediments are redistributed within the hillslope system, but also that a large proportion is delivered to the channel. These predictions have been tested by sampling the fine sediment content of the streambed at key locations along the channel network and comparing the observed patterns to those predicted by the soil erosion model. By linking topographic and soil characteristics with land cover data, it has been concluded that high intensity erosion tends to occur at contact between different vegetation covers, on barren lands and croplands, and 15-25% slopes poorly protected by vegetation. Erosion ""hot spots"" have been identified in the Pitman Creek HUC 05110001-90-130 and 05110001-90-050, both part of the Big Pitman Creek sub-basin, as well as in Mill and Falling Timber Creeks with lower intensity.
115

Assessment of Atrazine in a Rural Water Source: Rough River Lake, Kentucky

Sharp, Scotty 01 December 2006 (has links)
Atrazine [2-chloro- 4-(ethylamino)-6-(isopropylamino)-l,3,5-triazine], a widely used herbicide in US corn production, impacts quality of drinking water for many rural water supply systems. Four systems at Rough River Lake, Kentucky, have had high levels of atrazine in raw water and in some cases finished water that have exceeded the legal limit of 3 parts per billion (ppb). The Rough River Lake watershed is 1,700-km2, much of which is located in limestone karst. A hypothesis was developed stating that there would be higher concentrations of atrazine in the northeast section of the Rough River Watershed, located in Hardin County, due to the no-till corn production of the area and karst features. Surface and subsurface samples were collected from eighteen locations (including all major tributaries) within the study area. Sampling began during the Spring of 2005 growing season on a fourteen-day cycle and a twenty-eight day cycle during the fall and winter months. Atrazine concentrations rose at nearly all sites within weeks of the spring application in May, and then began to decrease by late July. Five locations had over 3 ppb for at least two sampling rounds. Two sites exceeded 10 ppb. Global Polynomial Interpolation Analysis was used as both a data exploration tool and a way to demonstrate a definite spatial and temporal pattern to atrazine within the study area. It was also concluded, the reservoir with its larger volume and lower water velocity plays a significant affect on a longer residence time of atrazine, while the tributaries showed lower concentrations of atrazine most likely due to higher velocity and smaller volume of water.
116

Take Me to the River: Revitalizing LA's Lost Monument

Childs, Erin 01 May 2012 (has links)
The tale of South Korea's Cheonggyecheon River is one to warm an urban environmentalist's heart. Cheonggyecheon runs through the center of Seoul, a bustling metropolis of ten million that has been the capital of Korea since the 14th century. The Japanese were the first to sacrice Cheonggyecheon on the altar of urbanization, turning the River into a sewage system during their 35 year occupation between 1910 and 1945. Already thusvdegraded, it was easy for later administrations to eventually completely cover the river with the Cheonggye Road and Cheonggye Elevated Highway between 1958 and 1976. Cheonggyecheon became an exemplar of the expendability of urban environments in the face of modernization and economic growth, particularly the need for transportation in a quickly developing city. In the early 1990s it was discovered that extensive repair would be necessary to maintain the Highway, and with heavy political leadership of Mayoral Candidate Myung-Bak Lee, now the president of South Korea, the decision was made to restore the river rather than repair the road (Park, 2006).
117

Reducing Lead and Selenium from Drinking Water Using Limestone-based Material

Tumati, Sindhu 01 May 2012 (has links)
Contamination of drinking water with metals is a major problem facing many areas of United States and the World. There is a need for an inexpensive remediation technology for the removal of metals in drinking water that can be applied to small rural water systems. This research will focus on the development of a process for removal of select metals from drinking water by limestone-based material. Metals in drinking water considered for this research include lead and selenium. Limestone-based material has demonstrated the potential to reduce select metals (lead, cadmium and arsenic) in drinking water, with the additional benefit of low-cost disposal of a stable waste product in ordinary landfills. Earlier research by the principal investigators using limestone-based material for drinking water treatment has clearly shown that this material can achieve metals removal of greater than 90 percent. This project will investigate techniques to improve removal efficiency of limestone-based material through adsorption and precipitation. This research will assist in the development of a granular adsorbent product that will remove metals and that can be manufactured and sold for use at the drinking water source, at point-of-use, or at point-of entry.
118

Maui's freshwater : status, allocation, and management for sustainability

Grubert, Emily 21 December 2010 (has links)
The water system on Maui Island in Hawaii is an integral part of the island’s infrastructure, affecting energy, agriculture, waste, and domestic systems. Both the built and the natural water systems are likely to be altered over the coming decades. Maui’s two major industries are agriculture and tourism, which compete for water and land resources. Maui faces high costs for food and fuel it must import, and agricultural efforts might shift from plantation-scale monocropping to energy production or diversified agriculture for food. Simultaneously, land use changes (like deforestation), climate change, and cyclical droughts affect Maui’s freshwater supply. Water planning and management based on careful assessment can be valuable tools for a community expecting that water will become increasingly scarce. Since water plays a large role in many other systems, choices about water allocation and use can help the island move toward solutions of multiple problems at once, including energy scarcity, coastal protection, and financial health. This work provides a dynamic snapshot of Maui’s current built and natural water systems, then analyzes two potential water management actions: pumped storage hydroelectric facilities built on existing reservoirs and use of secondary treated wastewater to irrigate biomass for power. Based on cost estimates and alternative solutions, neither of these applications are currently judged viable. / text
119

Defining Efficient Water Resource Management in the Weber Drainage Basin, Utah

Wilde, Keith D. 01 January 1976 (has links)
The Weber Basin Water Conservancy District is a state institution, but its primary function is collecting money for the U.S. Bureau of reclamation, to pay for the Weber Basin Project. Different classes of water users pay markedly different fees for identical Project services. More than half of the water developed by the Project is not used consumptively, yet supply facilities continue to be built in the Basin because they are less expensive to their owners than prices charged for the underused capacity of the Project. Paradoxically, some Basin residents are bitterly resentful to both the District and the Bureau, claiming that water rights formerly their own have, by means of the Project, been stolen. That is, both the enemies and the proponents of the Project adhere to the Western orthodoxy that water is scarce and drought imminent. The principal difficulty of this investigation lay in identifying the nature of the problem, for the situation seemed full of contradictions. Consequently, the primary contribution of the dissertation is an explanation of Basin circumstances that accounts for arresting observations without inconsistency or contradiction. The most important hypotheses are, therefore, empirical, or historical and institutional. Economics, according to Richard T. Ely and Frank H. Knight, is a set of principles concerning what ought to be, not empirical descriptions of what is. Consistent with that perspective, once the nature of the problem is clear, applications of economic principles is a prescriptive judgement of how the problem may be resolved. The most important empirical hypotheses are as follows: Water is not scarce in the Weber Basin; neither are storage and conveyance facilities. All are abundant, even redundant. Nevertheless in combination with certain institutional arrangements and sustained propaganda campaign, this very abundance contributes to persistence of the attitude that water is scarce. Redundant facilities thereby encourage even more unneeded development. What appears on first examination to be a case of misallocated water resources by discriminatory prices, turns out to be a problem of distributing the burden of paying for excessive, unwanted public works. Water itself is a free good in the Basin. Actual distribution of the repayment burden is partly ideological and partly pragmatic; partly a political choice and partly a bureaucratic decision; partly a manifestation of agrarian policy and partly what the traffic will bear. If water is free, it is not an economic good, and not a subject for economic analysis. The Basin has an ample water supply, but water may nevertheless be locally and periodically scarce. The water problem is therefore one of conveyance and timing. Control of timing requires storage. Conveyance requires energy, as well as aqueducts. In the Weber Basin, conveyance energy may be either the controlled flow of falling (mountain) water, or electrically powered pumps tapping abundant groundwater reservoirs. The water development problem is therefore, an issue of alternative capital facilities for the control and delivery of water (itself abundant). Efficient resource allocation in water development is consequently relevant at the investment level; it is not a matter of pricing water. In this case, the major investment decisions have already been implemented, and the problem is one of evaluating distribution of the repayment burden. The relevant economics literature is principles of equitable taxation, and of public utilities' pricing. Application to the basin situation produces a conclusion that present arrangements are as equitable as could be devised. Further redundant investment (inefficient use of resources), however, could be avoided if the State Engineer's Office took a harder line on requests to drill new wells. The information provided in this work could be the basis for making such a program popularly acceptable.
120

Water Resource Management : Social Behaviour, Cultural Norms and Societal Structures

Sjögren, Olivia January 2015 (has links)
Water shortage is one of the greatest challenges that the world faces today. International and national water initiatives are increasing simultaneously with the number of implemented drinking-water projects. The provision of sustainable safe drinking-water supply is here conceptualized through the Sustainable Livelihood Approach with the view of helping poor people secure their essential basic needs, improve their quality of health and increase their livelihood opportunities. However, a lot of drinking-water projects do not end up with satisfactory outcomes. Widespread results have demonstrated low quality water resource management, worsened access to water supply, constructions shutting down and not the least, that consumers have not been able to take advantage of their new basic drinking-water systems. Projects have often failed in remote rural areas in developing countries where strong social norms, cultural values and power structures prevail. The research is based on identifying and analyzing to what extent past drinking-water projects have addressed public participation and been aware of social, cultural and structural surrounding factors. By using Gunilla Åkesson’s sociological framework the research also addresses the role and value of sociological aspects in drinking-water projects. It is found that past projects have often failed to include public participation and lacked situational awareness to a sufficient extent. The research show the importance for projects staff, managers and technicians to take into account social behaviors, cultural norms and societal structures in the local environment and to provide local people with health awareness and education. By taking this into consideration it would enable people to change their behavior and take advantage of the improved drinking-water systems provided for them. In conclusion, there is a need to address more sociological aspects in water resource management in order to promote sustainable safe drinking-water supplies in remote rural areas in developing countries. It can be argued that this is not only applicable in drinking-water projects but also in other areas of fields within grass root development work.

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