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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.
121

Using the Rangeland Hydrology and Erosion Model to assess rangeland management practices on the Kaler Ranch

Ross, Morgan 26 July 2013 (has links)
<p> It is difficult to assess rangeland management practices at a hillslope scale because of the spatial and temporal variability of ecohydrological processes across a landscape. The Conservation Effects Assessment Project (CEAP) aims to provide a cost-effective method for quantifying benefits of conservation practices on rangelands. This study uses the Rangeland Hydrology and Erosion Model (RHEM) to develop a framework to assess rangeland management practices by quantifying sediment yield and runoff. Kaler Ranch, located in Eastern Arizona, was used as a study site because of their recently implemented rangeland conservation practices. Vegetation parameters were developed based on field data collected across the ranch and used to represent various rangeland management scenarios in RHEM. Peak flow and sediment yield rates were determined for each scenario using RHEM and were used as metrics to evaluate rangeland condition. RHEM provided an adequate method to evaluate the relative differences between upland rangeland management scenarios; however, it was less effective at evaluating changes in management practices within a riparian area.</p>
122

Integrative Control of Curly Leaf Pondweed Propagules Employing Benthic Bottom Barriers| Physical, Chemical and Thermal Approaches

Barr, Thomas Calhoun, III 21 November 2013 (has links)
<p> The effective management of submersed aquatic macrophytes depends on understanding their reproductive biology. <i>Potamogeton crispus </i> L. (curlyleaf pondweed, Potamogetonaceae) produces numerous asexual propagules that make traditional management difficult. It has spread to roughly half of the counties in California (USA) from alpine habitats such as Lake Tahoe to the tidally influenced Sacramento-San Joaquin Delta. Studies were conducted from May 2012 till October 2012 at the bench and mesocosm scales in Davis and Sacramento, California, to explore the effects of benthic barrier control measures on the propagules (turions) of <i>Potamogeton crispus. </i> The first study examined the effects of three benthic barrier materials (jute, polyethylene and rubber) on turion sprouting. Jute benthic barrier material allows some light and oxygen through the fabric, while polyethylene allows oxygen, but not light. Rubber barrier material blocks light and oxygen exchange. Turion viability, as determined by sprouting, was then assessed post-treatment. Results showed no significant differences at the bench-scale for the untreated control (100% sprouting, SE=0%), jute (100% sprouting, SE=0%), or polyethylene treatments (96.9%, SE=2.1%) (n=16 for all treatments, &alpha; = 0.05). Rubber treatments resulted in 48.4% sprouting (SE= 10.6%; n=16). Results for the mesocosm experiments showed significant differences between the control and the jute and polyethylene treatments (control = 98.4% sprouting, SE= 1.6%; jute = 71.9% sprouting, SE= 4.5%; polyethylene= 70.3% sprouting, SE= 4.7%, n=16 for all treatments). Jute and polyethylene treatments were not significantly different in the mesocosm experiment. The mesocosm experiment with the rubber barrier significantly reduced sprouting (29.7% sprouting, SE= 6.1%; n=16) compared to other treatments. While light had minimal impact on sprouting, anoxia appeared to be the main factor inhibiting sprouting using benthic bottom barriers. Barrier induced anoxic stress combined with herbicides may potentially offer enhanced efficacy. The second study explored enhancement of the impermeable rubber barrier material with dilute acetic acid loaded into cassava starch "pearls". Turions were exposed for two weeks and then assessed for viability via post-treatment sprouting protocol with and without hydrosoil at the bench- and mesocosm-scale. Results for the bench-scale showed that the 20.8 mmol L<sup>&ndash;1</sup> acetic acid treatment was not significantly different (p=.4231) compared to the untreated control (Tukey HDS; p&le;0.05). However, the 41.6 mmol L<sup>&ndash;1</sup> acetic acid treatment was highly significantly different from the control (p-value &lt; 0.0001) at the bench-scale, but did not completely inhibit sprouting (mean sprouting of 31.25% (<i>SE</i>= 11.97)). Complete inhibition of sprouting turions occurred for both experiments at and above acetic acid concentrations of 83.3 mmol L<sup>&ndash;1</sup> (SE= 0). Results showed that tapioca starch saturated with acetic acid and combined with impermeable benthic barriers may offer an effective chemical treatment for the control of <i>Potamogeton crispus.</i> The final study examined hot water exposures under the barriers to kill and inhibit sprouting in turions. Heated water circulated under an insulated benthic bottom barrier may potentially offer a simple non-chemical rapid method to target surface propagules on the sediment, subterranean propagules and young plants. Heated water was used to treat <i>P. crispus</i> turions at the bench and mesocosm scales (25&deg;C, 40&deg;C, 50&deg;C, 60&deg;, 70&deg;C and 80&deg;C exposures for 30 to 300 seconds). Heated water exposures inhibited sprouting turions at 50&deg;C and 60&deg;C at the mesocosm and the bench scales, however, did not completely inhibit sprouting for all time exposures except at the bench-scale 60&deg;C treatment for 300 seconds. For 70&deg;C and 80&deg;C treatment exposures, there was a slight difference at the 30 second exposure mark, but at 60 second and beyond, all 70&deg;C and 80&deg;C treatments provided 100% inhibition. The cost to raise the temperature 60&deg;C from ambient water temperature under the contained limited volume under insulated barriers is estimated to be approximately $2 per 9.3 m<sup>2</sup> (100 ft<sup>2</sup>) for 5 minute treatments or $3459 ha<sup>-1</sup> ($1400 acre<sup>-1</sup>).</p>
123

Examining the effect of government structure and size on the performance of Mississippi community water systems

Barrett, Jason Roy 12 May 2015 (has links)
<p> Mississippi has an abundant supply of underground aquifers which are utilized by community water systems as their source of drinking water. As the demand for water increases through the increasing population and the influx of industries, there is a need to manage the consumption and distribution of this valuable resource. Since its inception, the Mississippi drinking water industry has spawned new regulations, new management options, and creative ideas to promote a safer more efficient community water system. </p><p> The Mississippi State Department of Health-Bureau of Public Water Supply's Capacity Development Assessment is a comprehensive survey completed annually for every community water system in Mississippi. The Capacity Development Assessment will be used to gauge the quality of performance of the specified community water systems based exclusively on size classification, exclusively on government structure classification, and government structure by size classification. </p><p> Over the past 15 years, Mississippi has seen several centralization efforts occur, where a municipality, utility district, and/or a rural water association merges with one or multiple adjoining or close proximity community water systems. This results in one of the three main legal structures of government over community water systems increasing in size in an effort to heighten performance. This research has analyzed the size (population) and government structures of Mississippi community water systems and has determined that economies of scale do exist. Government structure alone does not have an effect on the performance of community water systems but size alone does have an effect on the performance of community water systems. Municipalities and rural water associations reach optimal performance at the medium size classification and utility districts reach optimal performance at the small size classification. </p><p> Regardless of the driving force, it is valuable to see that all of the Mississippi consolidating government structures are able to achieve optimal performance. Future state and/or federal legislatures, county governments, city governments, public water supply associations, and business economic drivers can benefit by knowing which structure(s) of community water system governance is the most productive and efficient when the time comes to explore the option of persuasion or mandates to increase viability or heighten performance. </p>
124

User Compliance, Field Efficacy, and Greenhouse Gas Emissions of an Ultraviolet Water Disinfection System and other Drinking Water Treatment Alternatives for Rural Households in Mexico

Reygadas Robles Gil, Fermin 27 March 2015 (has links)
<p> Many households in developing countries rely on contaminated and untreated drinking water sources, contributing to gastrointestinal illness and other health risks. Even piped water quality is often unreliable because of poorly-maintained treatment or distribution systems. Household water treatment (HWT) systems aim to enable users to treat their water at the point of use, making it safe to drink. While some HWT options have been successful in improving health in developing countries, low adoption and sustained use outside pilot projects and epidemiological trials remains one of the current challenges with this approach. Furthermore, Quantitative Microbiological Risk Assessment models predict that the health benefits from water quality interventions drop significantly with even occasional consumption of contaminated water. Therefore, to be effective, HWT options need to achieve high user compliance rates and provide safe water reliably. </p><p> I begin my thesis with an interdisciplinary analysis of the field of water, health, and development, followed by a description of my research study site. Using an interdisciplinary research approach, grounded in the local context, I led the development of an ultraviolet (UV) water disinfection system for rural households. This included an iterative process of design and field tests to create a user-friendly system and laboratory research to improve the performance of the technology. I also collaborated with a non-profit organization based in Mexico in the design of an implementation program to support the adoption and consistent use of the UV system. </p><p> Then I present the design and application of a stepped-wedge cluster randomized trial in rural Mexico to evaluate compliance with the implementation program and field efficacy of the UV system. I developed a framework that disaggregates and measures the components of compliance from initial adoption of a safe water practice to exclusive consumption of safe water. I applied this framework to measure compliance across intervention and control groups and to test if additional program components that improve convenience to users can be a cost-effective approach to increase compliance. I present evidence that the implementation program significantly improved compliance with the habit of consuming safe water, when compared to the practice of purchasing water bottled in reusable 20 L containers in the control group. The additional program components proved to be a cost-effective strategy to increase compliance immediately post-intervention, but their impact degraded with time. By analyzing results across different compliance components, I find limitations of the current HWT approach. I present the rational for pilot testing strategies outside the current HWT paradigm, such as expanding a narrow focus on drinking water to making all domestic water safe to drink or switching from a product-based to a service delivery model. </p><p> As a second component of the randomized trial, I present a series of controlled comparisons to evaluate the field efficacy of the UV system using <i> E. coli</i> as a fecal contamination indicator in drinking water. I use an as-treated-analysis to isolate the impact of the system and contrast these results with an impact evaluation of the implementation program led by a research colleague. I also created a drinking water reliability framework to compare potential contamination impacts from different household water management practices and a logistic regression model to assess household risk factors for post-UV-treatment contamination. I show that treating water with the UV system and storing it in 20 L narrow-necked containers, allowed households to significantly improve their drinking water quality and gain access to a more reliable source of safe water. </p><p> In the final chapter I investigate the greenhouse gas (GHG) emissions associated with the use of HWT technologies in Mexico. I do that by carrying out a literature review of existing studies assessing energy use of water treatment technologies; using secondary data to perform a life cycle assessment (LCA) capturing the embedded CO<sub>2</sub> equivalent emissions of individual HWT products; and developing model to calculate a metric of GHG emissions per volume of water used representative of the HWT sector in Mexico. Filtration, ozone, and UV disinfection technologies resulted in similar LCA emissions, while reverse osmosis had emissions five times higher than the average of the rest. I also find GHG emissions of HWT to be 30 times lower than water bottled in 20 L reusable containers. In a context in which mortgage institutions have created green credit mechanisms, this result is useful for expanding financing options for HWT products, which are often more cost-effective than bottled water, but require a higher capital investment. (Abstract shortened by UMI.)</p>
125

In-season Drought Monitoring| Testing Instrumentation and Developing Methods of Measurement Analysis

Raper, Tyson B. 28 August 2014 (has links)
<p> Soil moisture sensor use in crop production systems has the potential to give inference on plant water status for the purpose of irrigation scheduling and site-drought characterization. These processed measurements could serve as the framework on which to compile trial results across locations, thereby more accurately defining varietal yield response to drought. Still, the ability to characterize drought within a given field or initiate irrigations from these data hinge upon the ability of the instrument to characterize soil moisture at the sampled point and extrapolate that information across the landscape and time. Therefore, the objectives of this research were to: (1) test the response of the Watermark 200SS (Irrometer Company, Inc., Riverside, CA) and Decagon 10HS (Decagon Devices, Inc., Pullman, WA) to changes in water content of three dissimilar soils representing common soils in row-crop production under variable environmental conditions; (2) develop a soil moisture-based index to quantify drought stress in dryland cotton cultivar trials; and (3) determine if a limited number of soil moisture sensors deployed into a dryland cultivar trial could accurately characterize the VWC at a given point within the field and if this measurement could be extrapolated out to the field scale from the very small sphere of influence characterizing the utilized soil moisture sensors. During the 2012 and 2013 growing seasons soil moisture sensors were deployed into over 14 cotton cultivar trials across the U.S. Cotton Belt and into a water-input controlled container study. Tested sensors' inability to accurately predict container VWC emphasized the relatively small quantity of soil on which these sensors rely and the variability in soil moisture within a very limited volume. Results from the drought-index studies suggested both the Accumulated Soil Moisture Stress Index (ASMSI) and the relative reduction in evapotranspiration (1-(ET<sub>c adj</sub>/ET<sub>c</sub>)) appear to have potential in characterizing the amount of stress experienced within dryland cultivar trials. Analysis of spatial and temporal stability suggested trends between sensors were consistent, but absolute node readings varied. Optimism concerning the potential of these measurements/approaches for increasing water use efficiency is coupled with a call for more arbitrary, universal methods of measurement analysis.</p>
126

Exploring the Sustainability of Control of Qinhuai River: A case study in Nanjing, Jiangsu, China

Hu, Jingwei January 2014 (has links)
Qinhuai river in Nanjing, China, has suffered pollution since the late 1970s. To solve the problem, Nanjing Municipality conducted two river control projects. The first one in 2002 ended up a failure, and the second one in 2012 also faced various hinders. The aim of the thesis is to examine the sustainability of the river control launched in 2012, and to contribute with some suggestions for improvement. In this thesis, the author used methods of interview and literature review to gain the empirical data of the river control, used method of stakeholder analysis to analyze the data with the lens of sustainable development, Integrated Water Resource Management (IWRM) and externalities. After the analysis, the river control is considered unsustainable. The conclusion is that the pollution mainly originates from wasted domestic water. And the river control launched in 2012 is not sustainable as it lacks long-term perspective, social participation, gender awareness and solutions to mitigate the externalities. The emphasis is that, as the enabler, regulator and provision offer, Nanjing Municipality needs to raise social participation and internalize the environmental externalities to reach sustainable management of the Qinhuai river.
127

Resource management to rural residential| Tools to monitor parcelization in the Catskill Region of New York State

Pinkoski, Cassandra N. 20 November 2014 (has links)
<p> Parcelization is an increasing concern to land managers in the rural regions of the United States. In order to protect vital ecosystem goods and services, resource managers need to account for decreasing parcel sizes. The Catskill region of New York State contains both the New York City Watershed and the Catskill Preserve. In order to maintain ecosystem functions within these sensitive areas, wise planning is needed in the development of rural lands. This study documents the change in private, rural parcel dynamics from 2004 to 2010 in the Catskill region at the township scale. A parcel density map was developed to observe trends in distribution of small parcels. The average parcel size dropped from 13.9 acres in 2004 to 13.1 acres in 2010. The distribution of small private, rural parcels is diffuse across the study region, implying the transition from resource management focused land holdings to rural residential within the Catskill region.</p>
128

Supplementing soybean meal with Camelina (Camelina sativa) in tilapia diets and optimizing commercial tilapia diets for use in intensive systems in the Western region of the United States

Ramotar-John, Badule Pamila 21 October 2014 (has links)
<p> The feed production cost in tilapia diets is driven by the prices of its ingredients such as fishmeal (FM) and soybean meal (SBM). Fishmeal and soymeal combined with other ingredients provides fish with the nutrients required for growth and sustaining life. Soybean meal is used as an alternative to fishmeal, but prices for this traditional ingredient have increased significantly in recent years as a result of high market demand from other industries. Consequently, there has been an increase interest by tilapia nutritionists and feed manufacturers to find less expensive, alternative feedstuffs for use in tilapia diets. </p><p> Camelina <i>(Camelina sativa)</i> is an oil seed crop grown in higher latitudes especially along the US - Canada border, northern China and northern Europe. Camelina after removal of most of the edible oil has been proposed as a fish feed ingredient. </p><p> A sixty-day feeding trial was conducted and diets were formulated to contain various levels of camelina inclusion (0, 5, 10, 15, 20 and 25%) for the &ldquo;camelina meal&rdquo; while the &ldquo;camelina oil&rdquo; was formulated to contain one level (4.7%) of oil and was divided as &ldquo;raw&rdquo; and 4.7 &ldquo;wash&rdquo;. The results indicated that that fishes fed diets containing camelina ingredients had growth performance and feed utilization results that were similar to fish fed the commercial diet (P>0.05). There were significant differences (P&lt;0.05) for body organ indices and body composition. The 15% camelina meal diet was the lowest cost experimental diet per kilogram gain and therefore, this alternative ingredient might be a potential replacement for soymeal in a more cost effective feed formulation. </p><p> The fatty acid composition of tilapia fillets was also analyzed at the end of the feeding trial. The inclusion of camelina meal and oil in tilapia diets resulted in significant increases in the Omega-3/Omega-6 ratio in fillets when compared to the control. The 15% camelina meal provided the best results of the experimental diets yielding significantly higher polyunsaturated fatty acid (PUFA) and lower saturated fatty aid (SFA) than the control diet. </p><p> On a commercial scale, tilapia commercial feeds differ in both formulated nutrient levels and ingredient composition. In intensive system culture, natural food is limited making it important that all nutrients are supplied through a complete pelleted diet. An advantage to feeding a pelleted diet is that the pellet-type feed enables the farmers, feed formulators and manufactures to design a diet that provides an optimal nutritional mix for tilapia. </p><p> Precise levels in the protein and lipid percentages of tilapia diets can reduce feed costs and also reduce the amount of underutilized protein and lipids stored as fat in tilapia. Feed comprises of over 60% of the variable cost in the intensive aquaculture operation; if feed prices were to increase, it would be a substantial amount for tilapia producers to absorb. Therefore an improved diet formulation designed for tilapia can increase profitability. </p><p> Results indicated that the experimental diets (28% Crude Protein (CP)-Amino Acid (AA), 28% CP and 40% CP) performed similar to the control diet (32% CP) as it relates to fish growth. The experiment conducted on a commercial scale at an operating farm found that feeding tilapia the lowest protein level diets (28% CP) resulted in higher biomass gain per raceway, biomass gain per fish and significantly higher protein efficiency ratio (PER) when compared to the control diet (32% CP). The 28% CP diet also had the second best FCR value and most importantly higher returns based on its FCR when compared to the control diet (32% CP).</p>
129

Valuing water| A normative analysis of prior appropriation

Elbot, Morgan Bradfield 23 October 2014 (has links)
<p> This thesis aims to provide a normative evaluation of the Western U.S. water law of prior appropriation through a contextual analysis of water value pluralism. The first chapter begins with a preliminary account of the major justificatory arguments made in defense of prior appropriation, followed by two critiques that undermine some proposed advantages of the water policy. The purpose of this analysis is to elucidate the normative claims that underlie many of the arguments within this debate but which fail to be made explicit. It becomes clear that these normative claims assume a utilitarian criterion for resource distribution, according to which water is primarily viewed as an economic good with a monetary value. The second chapter challenges the legitimacy of this assumption by introducing non-monetary water values, with attention to the particular social and cultural contexts in which they emerge. Through a review of four economic proxies, these non-monetary water values are shown to be incommensurable with monetary valuations. Finally, the third chapter offers a theoretical framework for the incorporation of non-monetary water values into resource distribution decisions. From this normative analysis, it is concluded that a necessary condition for achieving just resource distribution decisions is for prior appropriation to incorporate value pluralism by recognizing the legitimacy of non-monetary water values.</p>
130

The social construction of water in Dominica and how it has influenced use and exportation

Pickering, Evelyn 28 January 2015 (has links)
<p> Dominica has been recognized for its landscape containing hundreds of rivers and receiving high rainfall, and "our water belongs to the world," or so says many Dominican citizens, and their government. A schism exists in the understanding of the water resources of Dominica. Local perceptions are in conflict with regional climate change data. Where climate change research has found Dominica to be high risk for water quality and quantity, locals maintain the mindset that there is an overabundance of the resource. Local epistemologies influence governmental water management practices, which presently focus on exportation of the resource. In efforts of economic development, while trusting that there is a surplus of water, Dominica leases billions of gallons of water each year to foreign companies. A popular conception on the island is that there is an abundance of water, and therefore, it should be shared globally. This unique social construction of Dominican water has been a foundation leading to the sale of billions of gallons of fresh water to international corporations. However, the bulk exportation of water is occurring in the context of climate change, and thus, the availability of water will be impacted by changes in annual rainfall, sea level rise, increased temperatures, and more severe hurricanes. The purpose of this study is to gain a better understanding of how the social understanding of water in Dominica was constructed, and what this means in relation to resource exportation and climate change. This research-based paper explores Dominican perceptions of water abundance and sustainability.</p>

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