• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 187
  • 117
  • 10
  • 8
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 363
  • 363
  • 363
  • 123
  • 116
  • 84
  • 77
  • 57
  • 55
  • 41
  • 36
  • 36
  • 32
  • 30
  • 30
  • 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.
31

Comparison method between gridded and simulated snow water equivalent estimates to in-situ snow sensor readings

Fabbiani-Leon, Angelique Marie 04 December 2015 (has links)
<p> California Department of Water Resources (DWR) Snow Surveys Section has recently explored the potential use of recently developed hydrologic models to estimate snow water equivalent (SWE) for the Sierra Nevada mountain range. DWR Snow Surveys Section&rsquo;s initial step is to determine how well these hydrologic models compare to the trusted regression equations, currently used by DWR Snow Surveys Section. A comparison scheme was ultimately developed between estimation measures for SWE by interpreting model results for the Feather River Basin from: a) National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) gridded SWE reconstruction product, b) United States Geological Survey (USGS) Precipitation-Runoff Modeling System (PRMS), and c) DWR Snow Surveys Section regression equations. Daily SWE estimates were extracted from gridded results by computing an average SWE based on 1,000 ft elevation band increments from 3,000 to 10,000 ft (i.e. an elevation band would be from 3,000 to 4,000 ft). The dates used for processing average SWE estimates were cloud-free satellite image dates during snow ablation months, March to August, for years 2000&ndash;2012. The average SWE for each elevation band was linearly interpolated for each snow sensor elevation. The model SWE estimates were then compared to the snow sensor readings used to produce the snow index in DWR&rsquo;s regression equations. In addition to comparing JPL&rsquo;s SWE estimate to snow sensor readings, PRMS SWE variable for select hydrologic response units (HRU) were also compared to snow sensor readings. Research concluded with the application of statistical methods to determine the reliability in the JPL products and PRMS simulated SWE variable, with results varying depending on time duration being analyzed and elevation range.</p>
32

Conceptual framework to estimate economic feasibility of groundwater banking on agricultural land

Rodriguez Arellano, Jose Luis 10 December 2015 (has links)
<p> Since 1865 California has practiced underground water storage through artificial recharge; however, in many parts of the state these efforts have been insufficient to meet its growing water demands, particularly for irrigated agriculture. During dry periods, vast agricultural areas depend upon groundwater for irrigation. In these areas, groundwater banking (GB) should be an essential strategy of their water management operations. GB is the practice of using surface water for percolation or injection into aquifers for later recovery. One variation of GB currently being studied in California is the use of agricultural lands for this practice (Ag-GB). Economic implications of Ag-GB need to be analyzed to inform water agencies and farmers interested in implementing this practice. This study proposes a conceptual model for determining the economic feasibility of Ag-GB at the irrigation district level. The Orland-Artois Water District (OAWD) in Glenn County is considered as the case study, and alfalfa as the test crop due to its tolerance to flooding and low use of pesticides and fertilizers which could leach into the aquifer. The proposed model consists of four components. The first component, the agricultural water demand calculator, calculates agricultural water demands based on historic land use, monthly reference evapotranspiration (ETo), monthly average precipitation, and average crop coefficient (Kc) values for the region. The second component, the aquifer mass balance model, is a one-bucket mass balance model that quantifies inflows and outflows to the simplified aquifer. The third component, the agronomic model, estimates costs and benefits of Ag-GB in terms of energy savings from pumping and crop production. The fourth component, the economic feasibility output, evaluates costs and benefits are evaluated to determine economic feasibility. The period of analysis is from 1993 through 2013. </p><p> Two policies (A and B) for implementation of Ag-GB are proposed and tested. Policy A proposes that all growers in OAWD pay for the implementation of the Ag-GB program. Policy B proposes that alfalfa growers using their lands for Ag-GB (Ag-GB alfalfa growers) are exempted from paying for Ag-GB implementation and the rest of the growers (non Ag-GB growers) pay for it. The economic analysis suggests that Policy A brings more costs than benefits to the Ag-GB alfalfa growers and hence is rejected as feasible. Policy B seems to bring more benefits than costs to all growers in OAWD and therefore it has potential to be economically feasible under the assumptions and limitations of the model. </p>
33

Effect of Municipal Waste Incinerator Bottom Ash on Nutrient Removal Efficiency in a Bioretention Column Study

Eichhorst, Jessica 17 November 2015 (has links)
<p> Nitrogen and phosphorus pollution in hydrologic ecosystems is a costly environmental problem. Low Impact Development measures, such as bioretention, can help prevent nutrient pollution. Bioretention is a type of green stormwater infrastructure and landscaping feature that collects, stores and treats stormwater runoff. Bioretention media is composed of sand, soil and an organic material such as compost or wood fines. While bioretention in itself is a sustainable practice, there is an ever growing demand for more sustainable solutions to the world's environmental problems. The St. Louis Metropolitan Sewer District's Lemay Waste Water Treatment (WWTP) incinerates biosolids, which creates a non-hazardous byproduct referred to as bottom ash. Incinerator bottom ash from the Lemay WWTP is mostly composed of silica and is very similar to sand. So, if incinerator bottom ash from the Lemay WWTP can be used in bioretention media as a substitute for sand, it will make a sustainable stormwater management technique even more sustainable. However, bioretention media with incinerator bottom ash will have to behave as a typical media to be an acceptable substitution. Nitrogen and phosphorus concentrations in the effluent from bioretention cells are of particular interest due to the drastic environmental issues associated with nutrient pollution. Therefore, a bioretention column study was performed to observe nutrient pollutant removal efficiency and plant compatibility of bioretention media containing municipal waste incinerator bottom ash. The results of the column study indicate that municipal waste incinerator bottom ash from the Lemay WWTP could be an acceptable substitution for sand in bioretention media.</p>
34

Scales of Sovereignty| The Search for Watershed Democracy in the Klamath Basin

Sarna-Wojcicki, Daniel Reid 07 November 2015 (has links)
<p> This dissertation examines the politics of knowledge in collaborative watershed governance institutions of the Klamath River Basin of Northern California and Southern Oregon. The waters of the Klamath are shared between farmers, fisherfolk, indigenous communities, hydro-electric facilities and one of the most biologically diverse eco-regions in the United States. Since 1986, the watershed has provided the primary spatial unit for resolving resource conflict by coordinating agency and citizen science, guiding integrated resource management and cultivating a shared sense of place and belonging among Klamath watershed inhabitants. For nearly three decades, the Klamath Basin has served as a laboratory for experiments in &ldquo;<i>watershed democracy</i>&rdquo;- a form of hydrologically-grounded political association that attempts to facilitate the direct participation of all watershed inhabitants in knowledge production, deliberation and collective action at the watershed scale. Through the idiom of <i>watershed democracy,</i> I connect empirical research on the outcomes of nearly three decades of community-based natural resource management in the Klamath with theoretical debates waged over the last century and a half regarding the question of scale in environmental science, democratic governance and natural resource management. </p><p> In this dissertation, I analyze the watershed as a scale of knowledge production, a site of democratic deliberation and a unit of environmental governance. I investigate whether the watershed is the most appropriate socio- spatial unit for representing people and place in the Klamath, paying particular attention to the impact of collaborative watershed governance arenas on the ability of Karuk Tribal members to participate in knowledge-production and decision- making for natural resource management in their ancestral territory in northern California. </p><p> Through participatory research with the Karuk Tribe&rsquo;s Department of Natural Resources, participant observation, document analysis and interviews with Federal, State, Tribal and local agency scientists and representatives, I follow knowledge and policy-making processes across a diverse range of institutions engaged in Klamath watershed governance. Combining participatory research and participant observation with theoretical insights from political ecology, science and technology studies (STS) and indigenous studies scholarship, I evaluate the processes and outcomes of collaborative watershed-based governance according to its impacts on local watershed ecosystems and communities. Drawing on the theoretical framework of &ldquo;co-production&rdquo;, I analyze the mutually constitutive relations between watershed science, watershed governance institutions, the materialities of Klamath watershed-ecosystems and the distributions of resource benefits and burdens in Klamath communities. I follow Klamath experiments in watershed democracy negotiate the basic terms of political life such as property, territory, sovereignty and the public good, as well as the material conditions and flows of watershed resources and the patterns of access to, ownership in and distribution of these resources. </p><p> While the Klamath experiements in collaborative environmental governance at the watershed scale have opened up oppportunities for Karuk representatives to participate in knowledge production and decision-making, the watershed scale has itself constrained the focus of integrated resource management, limiting the kinds of knowledge that can pattern as reliable and the types of restoration and management projects that can issue from Klamath collaborative governance forums. I demonstrate how Karuk representatives have both leveraged and critiqued the watershed as a way of conceptualizing Klamath watershed-ecological processes and as a socio-spatial unit for approaching ecological restoration and cultural revitalization in their ancestral territory. Watershed science and watershed governance forums were sometimes leveraged by Karuk representatives to substantiate Karuk sovereignty and resource rights and at times rejected for not being able to convey distinct Karuk epistemologies, ontologies and cosmologies. I demonstrate how collaborative watershed management forums have struggled to render different types of indigenous, local and scientific knowledge commensurable and have instead provoked debates about how to produce knowledge about nature in ways that are appropriate for the local community and its ecosystems. </p><p> I draw attention to the cultural politics of scale to critique watershed-centric management and search for alternative ways of representing the multiple scales through which Klamath inhabitants understand and value nature. I compare watershed-based governance with two other emerging scales of democratic resource governance- firesheds and foodsheds- in their abilities to bring together diverse forms of environmental knowledge around multiple nested scales of social and ecological processes. <i>Firesheds</i> are emerging areas of community-based fire management patterned according to the way fire burns across the western Klamath landscape. <i>Foodsheds</i> are another emerging form of community-based resource governance taking shape in the Klamath around the spatial and temporal characteristics of food resources and their associated management practices in forest ecosystems. Comparing watersheds, firesheds and foodsheds opens up the question of scale in collaborative environmental governance by highlighting tensions among different ways of producing knowledge, managing resources and acting collectively at different bioregional scales in the Klamath. </p><p> Against watershed-centric approaches to ecological democracy, I argue for deliberative multi-scalar approaches to implementing collaborative environmental governance, cultural revitalization and watershed-ecosystem restoration in the Klamath. Multi-scalar perspectives can accommodate multiple ways of making knowledge while avoiding homogenizing diverse situated perspectives into a single way of seeing Klamath eco-cultural landscapes. I argue for <i> &ldquo;democratizing scale&rdquo;</i> in order to define an appropriate scalar framework for producing knowledge, representing human values and making decisions about the management of natural resources. Collaborative environmental governance requires an accompanying democratization of scale to accommodate the myriad ways of knowing nature and making a living in Klamath watershed-ecosystems. Scalar formations that are produced through deliberative democratic processes can provide more inclusive grounds than watersheds for democratic environmental governance and multispecies world-making.</p>
35

A study of urban residential water consumption behaviour : the case of Kuwait

Husain, Salman Y. Y. January 2000 (has links)
No description available.
36

Sustainability and water resources management for the northern Adelaide Plains, South Australia /

Fleming, Nicholas S. January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 1999? / Includes bibliographical references (64 p. ).
37

Environmental and management considerations in the design and operation of water supply facilities /

Chan, Koon-leung, Jeffrey. January 1900 (has links)
Thesis (M. Sc.)--University of Hong Kong, 1994. / Includes bibliographical references.
38

Hydrodynamic modeling of the Green Bay of Lake Michigan using the environmental fluid dynamics code

Cedillo, Paula 13 January 2016 (has links)
<p> In this project we created a hydrodynamic model of the Lower Green Bay of Lake Michigan in Wisconsin, United States using the Visual Environmental Fluid Dynamics Code (EFDC). The model includes four tributary rivers to Lower Green Bay as well as the open boundary flow conditions at Chambers Island. This case study is used to: 1) compare the results obtained with a previous study of Lower Green Bay to validate the creation of the model 2) examine the hydrodynamics of the bay, and 3) create a framework for future studies at Lower Green Bay. The Geographic Information used to build the Grid was obtained from the NOAA web site. Meteorological and flow information was obtained from the National Weather Service and USGS web sites, respectively. It was necessary to create a new model grid as a platform for future studies of Lower Green Bay, and the Visual EFDC 1.2 code was a useful tool in the development of the grid. However, some limitations in the code made the creation of the grid a challenge. In this project, we summarize the process used to overcome challenges in creating a correct grid, and analyze the hydrodynamic results of the model simulation for the period between June and October 2011. Overall, we conclude that the model reproduces field data reasonably well, and a correct modeling framework for hydrodynamic modeling of Lower Green Bay was created. </p>
39

Changing social norms| California friendly gardens in Long Beach, CA

Davis, Rachel H. 11 December 2015 (has links)
<p> The Lawn to Garden Program incentivizes replacing front yard turf grass with California Friendly gardens in Long Beach, CA. The Long Beach Water Department introduced the program in 2009 as a means of water conservation and since that time 2% of the City&rsquo;s single-family homes have successfully completed the program. As of the end of 2014, 3,461 applications had been submitted, but only 1,849 Lawn to Garden projects had been completed, a success rate of 53% and withdrawal rate of 47%. This study seeks to identify some of the factors that contribute to the program&rsquo;s high withdrawal rate, exploring the resources available to participants as well as the barriers to success. Methods used include geographic analysis in the form of density mapping, analysis of survey responses submitted by participants who withdrew from the program, and my professional observations. This study considers which neighborhoods display greater rates of success and withdrawn applications as well as what resources would have most aided those who did not complete their projects. </p>
40

Development of a Microwave - Remote Sensing Based Snow Depth Product

Diaz, Carlos Luis Perez 07 August 2018 (has links)
<p> Snow is a key component of the Earth&rsquo;s energy balance, climate, environment, and a major source of freshwater in many regions. Seasonal and perennial snow cover affect up to 50% of the Northern Hemisphere landmass, which accounts for vast regions of the Earth that influence climate, culture, and commerce significantly. Information on snow properties such as snow cover, depth, and wetness is important for making hydrological forecasts, monitoring climate change, weather prediction, and issuing snowmelt runoff, flash flood, and avalanche warnings. Hence, adequate knowledge of the areal extent of snow and its properties is essential for hydrologists, water resources managers, and decision-makers. </p><p> The use of infrared (IR) and microwave (MW) remote sensing (RS) has demonstrated the capability of estimating the presence of snow cover and snowpack properties with accuracy. However, there are few publicly accessible, operational RS-based snow depth products, and these only provide the depth of recently accumulated dry snow because retrievals lose accuracy drastically for wet snow (late winter - early spring). Furthermore, it is common practice to assume snow grain size and wetness to be constant to retrieve certain snow properties (e.g. snow depth). This approach is incorrect because these properties are space- and time- dependent, and largely impact the MW signal scattering. Moreover, the remaining operational snow depth products have not been validated against in-situ observations; which is detrimental to their performance and future calibrations. </p><p> This study is focused on the discovery of patterns in geospatial data sets using data mining techniques for mapping snow depth globally at 10 km spatial resolution. A methodology to develop a RS MW-based snow depth and water equivalent (SWE) product using regression tree algorithms is developed. The work divided into four main segments includes: (1) validation of RS-based IR and MW-retrieved Land Surface Temperature (LST) products, (2) studying snow wetness by developing, validating, and calibrating a Snow Wetness Profiler, (3) development of a regression tree algorithm capable of estimating snow depth based on radiative (MW observations) and physical snowpack properties, and (4) development of a global MW-RS-based snow depth product built on the regression tree algorithm. </p><p> A predictive model based on Regression Tree (RT) is developed in order to model snow depth and water equivalent at the Cooperative Remote Sensing Science and Technology Center &ndash; Snow Analysis and Field Experiment (CREST-SAFE). The RT performance analyzed based on contrasting training error, true prediction error, and variable importance estimates. The RT algorithm is then taken to a broader scale, and Japan Aerospace Exploration Agency (JAXA) Global Change Observation Mission &ndash; Water 1 (GCOM-W1) MW brightness temperature measurements were used to provide snow depth and SWE estimates. These SD and SWE estimates were evaluated against twelve (12) Snow Telemetry (SNOTEL) sites owned by the National Resources Conservation Service (NRCS) and JAXA&rsquo;s own snow depth product. Results demonstrated that a RS MW-based RT algorithm is capable of providing snow depth and SWE estimates with acceptable accuracy for the continental United States, with some limitations. The major setback to the RT algorithm is that it will only provide estimates based on the data with which it was trained. Therefore, it is recommended that the work be expanded, and data from additional in-situ stations be used to re-train the RT algorithm. The CREST snow depth and water equivalent product, as it was named, is currently operational and publicly accessible at https://www.noaacrest.org//snow/products/. </p><p>

Page generated in 0.1406 seconds