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Simulation of Runoff and Pollutant Loss in Urbanizing WatershedsZeckoski, Rebecca Winfrey 31 July 2002 (has links)
The effect of urbanization on previously agricultural watersheds is an increasingly important issue for watershed planners. Urbanization increases runoff and pollutant loadings to the watershed outlet. Watershed planners in areas that previously had little impervious cover must now consider the effects of new roads and buildings on hydrologic processes. The ANSWERS-2000 watershed model was modified to simulate watersheds with mixtures of agricultural and urban areas. In addition, components were added to simulate atmospheric deposition and urban management practices, including wet ponds, dry ponds, and infiltration trenches.
The modified model was evaluated on two watersheds in Blacksburg, Virginia, including a subwatershed of Stroubles Creek and a large parking lot on the Virginia Tech campus with a dry pond at its outlet. The model predicted the hydrology and pollutant losses for the year 1999 from the Stroubles Creek watershed within 50% of the observed values after calibration. Prediction errors were much higher for the parking lot and dry pond simulation of the period of time from August 1995 to February 1996. For the parking lot inflow to the dry pond, errors ranged from 0 to 100%. For the dry pond effluent, errors for runoff and sediment losses were -11.5 and 60.1%, respectively, and nutrient losses were poorly predicted (greater than 100% error). There was considerable uncertainty as to the quality of the observed data and this may account for some of the predicted sediment and nutrient loss errors. The modified model was applied to the Battlefield Green Watershed in Hanover County, Virginia to demonstrate the watershed response to development in that watershed. As simulated, sediment and nutrient losses were 30 to 50 times higher after development.
The model is intended for use on watersheds with an impervious cover of 30% or less, due to the increased difficulty in accurately quantifying the hydrology of highly urbanized watersheds and because of uncertainty in atmospheric deposition rates on such watersheds. The pond subroutines are very simplified, and limit simulation to ponds with simple geometries. / Master of Science
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Cultural dynamics of African management practiceIguisi, Osarumwense V. January 2009 (has links)
This research study looked at the cultural value preferences in Western management practice for African manager and non-manager employees exemplified by Nigerian cement industries. The study specifically focused on management practice of leadership, motivation, recruitment and promotion around which their cultural values, the meaning of their work-world and their coping strategies are structured. From management and culture theory perspectives, managerial practices are affected both by Western factors, such as education, money, challenging tasks, and by traditional factors, such as family, ethnicity, social connections etc. The theoretical bases for this study drew largely from three streams of literature. The first theoretical base for the study relates to traditional African environment of management, especially the cultural perspectives. The second drew largely from the theoretical discourse on culture, management and organisation perspectives. The mainstream schools of management discourse on management theories and models as proposed by Western management theorists represent the third stream. As a methodology, the study used a quantitative questionnaire survey and qualitative open-ended interviews to collect data on the manager and non-manager employees in the organisations. The quantitative questionnaires and open-ended interviews centered national dimensions of cultures and on these Western and traditional factors of: leadership styles, motivation, dedication, satisfaction, ethnicity, family and social connections. The survey confirms that the dimension of national cultures of Nigeria as measured by the work-values and desires of the employees population are somehow different from those obtained by Hofstede’s study for the West African Region. Nigeria is still more collectivistic, although at least Nigeria has become relatively more individualist since Hofstede’s study. Over the years between Hofstede’ IBM study and the present study, there has been no change in the difference in Power Distance. Power Distance is much higher in Nigeria, like elsewhere in Africa, and this is unlikely to change for the foreseeable future. The large Power Distance in Nigeria means that the ideal manager is benevolent paternalistic. On recruitment and promotion, one major point made is that the traditional factors are generally felt by the respondents as influencing employees’ recruitment and promotion more than the modern (intrinsic) factors. The employees however, generally felt that the modern (intrinsic) factors should or ought to have greater influence. Building on the premises that every society is unique and its trajectory is shaped by its unique historical events, cultural norms and values, it can be argued that since the history of Western management concept in Africa is short, Africa then has a unique opportunity to develop its own unique management values based on its unique traditions. However, the increasing globalisation of market economies suggests that management values in Nigeria in particular and Africa in general can hardly be realised without proactively contributing to the Western management concepts in its unique ways. As the intensity of interaction between Western management practices and African traditional values increases, we can anticipate the increase in the importance of a new form of management concepts and practices in various African countries. Based on others and this study, the study proposes a “management heterogeneity” concept that reflects this new and unique perspective. Management heterogeneity perspective endorses the view that the practice of leadership, motivation, recruitment and promotion are developed differently in different cultural societies and organisations. But it adopts a pragmatic position on the mounting social and economic challenges now facing African organisations and argues further that management techniques, skills and behaviours practiced in different cultures and organisations can be brought together in a positive synergistic blend to address the needs of a given society and organisation and improve its ability to deliver effective and relevant values to its actors. It is the ability to judiciously select and combine the Western and traditional values and practices into new practices that fit the managerial requirements of a given group of organisational members that provides management its competitive edge in a culturally dynamic management environment.
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Food Safety Management Practices of Small and Medium Sized Food Industry Enterprizes in TanzaniaKahindi, Bright Barestus 01 April 2016 (has links)
The study aimed to investigate the food safety practices of HACCP and ISO2200 in food establishments in Tanzania, focused on knowledge (awareness) and management practices of food safety systems. The research randomly surveyed 200 food establishments from three regions in the country; only 113 managers completed the survey. Research conducted face-to-face by questioning knowledge (employees and managers), management practices (ISO 22000, HACCP and prerequisites programs, GMP and SSOP), and demographic information. Employees indicated to have more knowledge on the use of GMP (64.3 %) than HACCP (22.9%) and ISO22000 (15.4%) and training of employees was GMP (73.9 %), ISO22000 (19.2 %) and HACCP (27.1%). This knowledge was also measured by frequency of training results, which indicated inadequacy of twice per year almost 31.4 % for manager, and every 3 months (29.1%) employees.
Management practices of food safety systems indicated HACCP practices were inadequately done by only 26.6 % of food establishments by validating quality assurance and monitoring systems. This also included the management pratices of barriers and benefits of food safety systems (ISO 22000 and HACCP). Barriers indicated poor confidence in suppliers to provide appropriate raw material (25.7 %), lack of government support (17.3 %) and the least 4% volume of paperwork. While, benefits indicated 68.6 % benefits as the highest with the lowest (22.7%) increase in product price. The improperbarrier implemenatation resulted into inadequate control of hazards under the HACCP program, only 40 % of the food establishments asserted all food in storage was protected from contamination.
Prerequisite programs in food establishments were fairly managed, over 80 % had well-designed draining systems within their food establishments.The least (35.5%) had written sanitation standard operation procedure for cleaning and disinfectants.
It is suggested that through job training, class training on food safety, and availability of resources, knowledge as well as management practices could be improved within food establishments. Further studies should focus on customer awareness, food vendors as well as single groups within the food industries.
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Constructed farm wetlands (CFWs) designed for remediation of farmyard runoff : an evaluation of their water treatment efficiency, ecological value, costs and benefitsGouriveau, Fabrice January 2009 (has links)
Farmyard runoff, i.e. the effluent generated by the rain falling over farmyards, tracks and roofs, is a significant and overlooked source of nutrients and pathogens which degrades aquatic ecosystems through eutrophication, siltation and wildlife poisoning, raises public health concerns, and incurs considerable costs for society. Among other Best Management Practices implemented to address agricultural water pollution and help achieve compliance with the Water Framework Directive, Constructed Farm Wetlands (CFWs), i.e. shallow surface flow wetlands comprising several vegetated cells in series, are being recommended for remediation of farmyard runoff, due to their capacity to remove or store pollutants. Investigation is therefore needed of their long-term water treatment efficiency and ecological value to optimize their design and cost-effectiveness and minimize their negative externalities. The main aims of this study were to: 1) evaluate the treatment performance of CFWs and the link between design, hydrology and efficiency; 2) assess their ecological value and the influence of water quality and design on wetland ecology; 3) identify their costs, benefits and the way they are perceived by farmers; and 4) inform guidelines for the design, construction and aftercare of sustainable CFWs. Research focused on two CFWs in south-east Scotland, one at a dairy farm and one at a mixed beef-arable farm, which receive runoff from yards and roofs, field drainage and septic tank overflow. From February 2006 to June 2008, rainfall, evaporation, water levels and flow at the CFWs were monitored, and their treatment efficiency was assessed from water samples collected manually regularly or with automatic samplers during storm events, and analysed using standard methods. In addition, their ecological value was assessed twice a year from vegetation and aquatic macroinvertebrate surveys. Finally, semi-structured interviews with eight farmers and a farm advisor and discussions with three CFW designers in Scotland and Ireland allowed collection of technical and economic data on farm practices, CFW construction and maintenance, and helped assess CFW cost-effectiveness and acceptance by farmers. Both CFWs reduced pollutant concentrations between inlet and outlet, with efficiencies at CFW1 and CFW2 respectively of 87% and < 0% for five-day biochemical oxygen demand, 86% and 83% for suspended solids, 68% and 26% for nitrate/nitrite, 42% and 34% for ammonium, and 12% and 31% for reactive phosphorus. Nevertheless, the concentration of all pollutants at the outlet of CFW1, and concentration of nitrate/nitrite at the outlet of CFW2 frequently exceeded river water quality standards. Water treatment efficiency varied seasonally, being significantly lower in winter, mainly due to lower temperatures, increased volume of inputs and reduced residence time. The ecological value of the two CFWs differed greatly. At CFW1 and CFW2 respectively, 14 and 22 wetland plant species and 24 and 46 aquatic macroinvertebrate species (belonging to 13 and 27 BMWP scoring families respectively) were recorded, illustrating the greater biodiversity conservation value of CFW2, which was one year older, larger, cleaner, comprised several ponds with a combination of open water and densely vegetated areas, and was subsequently more structurally diverse. The socio-economic study revealed that, despite significant costs associated with their construction (£20 000-£50 000 ha-1) and maintenance (£900-£1500 ha-1 yr-1), CFWs may still represent a more cost-effective alternative than conventional methods. However, their adoption, implementation and sustainable use by farmers were conditioned by land availability and suitability, existing farm infrastructure, detailed information on limitations and maintenance requirements, and adequate financial support for both construction and aftercare. To ensure a long-term, consistent and efficient water treatment, and to enhance biodiversity and landscape, well-maintained, large, vegetated, multi-cell CFWs with shallow overflows are recommended. Their size should be adapted to local precipitation patterns and catchment characteristics. Keywords: agriculture, best management practice (BMP), biodiversity, constructed farm wetland (CFW), costs, farmyard runoff, water pollution, water treatment.
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Sustainable Agriculture in Vermont: Economics of Climate Change Best Management Practices and the Complexity of Consumer Perceptions of Raw MilkHelling, Alexander Paul 01 January 2015 (has links)
Changing weather patterns, the declining social fabric of rural communities, and economic uncertainty increasingly pose challenges to Vermont communities. The socially and environmentally embedded production practices within sustainable agriculture present a potential solution to these problems. In order to make the most of the potential benefits of these practices society must maximize their adoption. This requires an understanding of both farmer adoption of these practices and consumer perceptions of the resulting food products. This thesis contributes two original articles on sustainable agriculture through the analysis of factors driving both farmer adoption and consumer perceptions of products and practices often thought of as sustainable.
The first article seeks to understand farmer adoption of climate change best management practices (CCBMPs). Farmer perceptions of risk and profitability of best management practices (BMPs) are key determinants of adoption, which traditional incentive programs like the Environmental Quality Incentives Program (EQIP) attempt to address by providing financial and technical support. To ensure appropriate price points are offered through these programs, regional price structures must be based upon locally established costs. Thus, this article focuses on the economic cost of implementing and maintaining CCBMPs for twelve diverse farms in Vermont. Specifically, three CCBMPs for Vermont are examined: cover cropping, management intensive rotational grazing (MIRG), and riparian buffer strips. Results of a yearlong farmer based data collection process indicate that the average cost for cover cropping is $129.24/acre, for MIRG is $79.82/acre, and for a tree based riparian buffer strip is $807.33/acre. We conclude that existing incentive payments for cover cropping and MIRG are below costs, likely resulting in under-adoption.
The second article reports on a study which seeks to understand the factors influencing Vermont consumer perceptions of raw milk safety. While this article makes no assertion regarding the sustainability of raw milk, an association is established between the motivations for raw milk consumption and sustainable agriculture support. Vermonterâ??s appear to be continuing the trend of consuming raw milk at an increasing rate despite continued declarations from local and national public health officials that raw milk is too microbiologically dangerous to justify its consumption. Thus this study was designed to increase understanding of the factors driving consumer perceptions of raw milk safety. A conceptual model was developed to establish potential factors and related questions were incorporated into the 2014 Vermonter Poll. Resulting data were analyzed using a Probit regression analysis. We conclude that observable factors have the greatest influence on perceptions of raw milk safety. Specifically, perceived health benefits, presence of children in the household, and taste all influence perceptions of raw milk safety.
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Towards an Understanding of Management Style Differences between China and Sweden : Based on impressions from 5 Chinese R&D employees in SwedenGuo, Wanli, Li, Zhen January 2009 (has links)
<p>With the world becomes closer, the issue of understanding management and culturedifference is getting more and more important. The purpose of this research is to findhow culture factors impact management style in China and Sweden. The study usedHofstede’s five cultural dimensions, traditional management practice and Denison’smodel of organizational culture and effectiveness as framework to identify whatdifferent management styles exist between two countries, as well as explain why thedifference occurs in term of national culture dimensions and traditional managementpractice.The interviews were made by five Chinese employees whom have work experiencesin China and now are working in Swedish organization in Sweden. From theirperspectives, the paper found the dimension of involvement and consistency issignificant different between two countries, which reflects on the aspects of teamorientation, empowerment, capability development, agreement, coordination andintegration. Moreover, Swedish companies are easier to adopt advanced technologyand innovation than Chinese companies. In general sense, it seems to Swedishorganizations obtain higher learning capacity than Chinese organizations. Finally, thispaper pointed out that both countries have a long-term strategy, but it’s more realisticin Sweden.Subsequently, those differences were analyzed by national culture, namely, Hofstede’sfive culture dimensions, and the traditional management practices in China andSweden. After discussion and analysis, the study found: the small power distance,feminine value and lower uncertainty avoidance as well as lower hierarchy are thereasons of Swedish management style such as high level of agreement, goodcommunication, and high capability development in Sweden. Meanwhile, the largepower distance, masculine value, high uncertainty avoidance, guanxi and paternalismstyle of leadership are the mainly reasons of Chinese management style such likelower level of team orientation, ineffective and lower learning capacity in China. Inaddition, the long-term orientation cause Chinese organization like to have a longtime planning, but the paternalism style of leadership induce the strategy of companydeparts from the reality. It has to note that the limitation of this study is the smallnumber and the limited scope of interviewees. Finally, it is suggested that Chineseorganization should learn several advanced management methods from Swedishorganization.</p>
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Towards an Understanding of Management Style Differences between China and Sweden : Based on impressions from 5 Chinese R&D employees in SwedenGuo, Wanli, Li, Zhen January 2009 (has links)
With the world becomes closer, the issue of understanding management and culturedifference is getting more and more important. The purpose of this research is to findhow culture factors impact management style in China and Sweden. The study usedHofstede’s five cultural dimensions, traditional management practice and Denison’smodel of organizational culture and effectiveness as framework to identify whatdifferent management styles exist between two countries, as well as explain why thedifference occurs in term of national culture dimensions and traditional managementpractice.The interviews were made by five Chinese employees whom have work experiencesin China and now are working in Swedish organization in Sweden. From theirperspectives, the paper found the dimension of involvement and consistency issignificant different between two countries, which reflects on the aspects of teamorientation, empowerment, capability development, agreement, coordination andintegration. Moreover, Swedish companies are easier to adopt advanced technologyand innovation than Chinese companies. In general sense, it seems to Swedishorganizations obtain higher learning capacity than Chinese organizations. Finally, thispaper pointed out that both countries have a long-term strategy, but it’s more realisticin Sweden.Subsequently, those differences were analyzed by national culture, namely, Hofstede’sfive culture dimensions, and the traditional management practices in China andSweden. After discussion and analysis, the study found: the small power distance,feminine value and lower uncertainty avoidance as well as lower hierarchy are thereasons of Swedish management style such as high level of agreement, goodcommunication, and high capability development in Sweden. Meanwhile, the largepower distance, masculine value, high uncertainty avoidance, guanxi and paternalismstyle of leadership are the mainly reasons of Chinese management style such likelower level of team orientation, ineffective and lower learning capacity in China. Inaddition, the long-term orientation cause Chinese organization like to have a longtime planning, but the paternalism style of leadership induce the strategy of companydeparts from the reality. It has to note that the limitation of this study is the smallnumber and the limited scope of interviewees. Finally, it is suggested that Chineseorganization should learn several advanced management methods from Swedishorganization.
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Noncompliance, monitoring and the economic theory in carbon trading marketMihal, Daniela 11 August 2008
Addressing climate change is a major undertaking. Agricultural soil has the potential to assist in decreasing the concentration of GHGs in the atmosphere by storing CO2 in the soil. Carbon offset markets have been suggested as a cost effective means of reducing GHG emissions. Farmers can increase their soil sink potential by applying Beneficial Management Practices (BMPs) that enhance carbon sequestration through improvements to soil, nutrient and livestock management practices (Fulton et. al., 2005). Whether or not a market for carbon offsets will emerge depends on a number of factors which mainly are related to the profitability of the BMPs and the costs of implementing a carbon contract. Provided that a market for carbon offsets emerges, the effectiveness of the market depends, in part, on the degree to which buyers and sellers in the market comply with the terms of the contracts they sign. The resource costs associated with monitoring and verification may result in incomplete monitoring. As long as monitoring is not perfect, non-compliance will be an issue. <p>The analysis that will be performed in this thesis introduces non-compliance in the economic analysis of carbon-offset market. The purpose of this work is to examine the overall cost effectiveness of the carbon-offset market when introducing non-compliance. <p>Firstly the theoretical model investigates the incentives for different farmers to participate in the carbon offsets market as well as incentives for engaging in cheating. The model recognizes farmers heterogeneity with respect to cost differences and examines the economic determinants of farmers non-compliance as well as the consequences of non-compliance on the performance of the carbon-offset market. Results support the standard finding that the extent of producers non-compliance decreases with an increase in the audit probability and/or an increase in the penalty per unit of non-compliance. In addition, the number of producers participating in the carbon offsets market is shown to increase with an increase in the carbon-offset price.<p> The analysis then introduces intermediaries in the market that will take care of trading carbon offsets as well as monitoring producers. The traders role in this study is played by an IOF (investor owned-firm) or a PA (producers association). Within the IOF, the analysis focuses on the monopoly and oligopoly structures. The key role of the traders is to guarantee, based on the amount of monitoring that is undertaken, that the emitters purchase only carbon offsets that actually correspond to sequestered carbon. The analysis then examines three cases for the group that monitors farmers compliance a group owned by for-profit traders, a government-run agency and a group owned by the PA trader. This part of the thesis examines what impact the involvement of the traders in the carbon-offset market has on non-compliance, as well as how the structure of the monitoring group affects non-compliance and the amount of carbon offsets traded in the market. The results of the analysis show that the monitoring groups always undertake sufficient monitoring to ensure that full compliance is achieved thus, while non-compliance is possible, it does not occur in equilibrium. The finding suggests that the formation of a government monitoring agency can potentially increase traded output and lower the price paid by emitters, still these changes are likely to be small, particularly when the trading sector is monopolistic. The overall analysis in this chapter shows that the optimal amount of enforcement, and as a result the cost effectiveness of a carbon-offset market, depends on the nature of the organization that undertakes the enforcement. <p>The next consideration of the thesis is the heterogeneity attributed to the timing of sequestration by different farmers. The analysis focuses on the carbon offsets pooling by considering two structures for the aggregator: a for-profit aggregator and a producers association. Pooling resources enables the farmers to benefit from economies of scale. The pricing schedule used by the aggregator is a two-part tariff. The two-part tariff is used as a way of providing an incentive for the farmers sequestering large amounts of carbon to participate in the pool. The study considers two alternatives for the coefficients that might be used to decide on the amount of carbon offsets to which each farmer will be entitled: default coefficient and custom coefficients. Each situation is modeled in a principal agent framework. <p>The analysis examines how the aggregator will target the monitoring service for different group of farmers. The investigation reveals that, under different scenarios, a PA or a FPA (for-profit aggregator) might lead to the formation of a heterogeneous pool or a homogeneous pool of each type. <p>The last issue investigated in this dissertation is the coexistence of a FPA and a PA in the default coefficient case. The analysis show that both aggregator structures can exist together in the market in the same time if the savings in the monitoring costs made possible by the PA are smaller than the cost of organizing the pool. If this condition is not satisfied the FPA cannot survive in the market and the producers association will dominate. <p>In addition to providing a better understanding of how the carbon-offset market may perform when introducing non-compliance, the results of this study can assist in assessing the cost effectiveness of the carbon-offset market when enforcement is undertaken by different organizations. Furthermore, the last consideration of the pooling option might help in selecting which type of pool a heterogeneous or a homogeneous one might perform better under different alternatives.
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Noncompliance, monitoring and the economic theory in carbon trading marketMihal, Daniela 11 August 2008 (has links)
Addressing climate change is a major undertaking. Agricultural soil has the potential to assist in decreasing the concentration of GHGs in the atmosphere by storing CO2 in the soil. Carbon offset markets have been suggested as a cost effective means of reducing GHG emissions. Farmers can increase their soil sink potential by applying Beneficial Management Practices (BMPs) that enhance carbon sequestration through improvements to soil, nutrient and livestock management practices (Fulton et. al., 2005). Whether or not a market for carbon offsets will emerge depends on a number of factors which mainly are related to the profitability of the BMPs and the costs of implementing a carbon contract. Provided that a market for carbon offsets emerges, the effectiveness of the market depends, in part, on the degree to which buyers and sellers in the market comply with the terms of the contracts they sign. The resource costs associated with monitoring and verification may result in incomplete monitoring. As long as monitoring is not perfect, non-compliance will be an issue. <p>The analysis that will be performed in this thesis introduces non-compliance in the economic analysis of carbon-offset market. The purpose of this work is to examine the overall cost effectiveness of the carbon-offset market when introducing non-compliance. <p>Firstly the theoretical model investigates the incentives for different farmers to participate in the carbon offsets market as well as incentives for engaging in cheating. The model recognizes farmers heterogeneity with respect to cost differences and examines the economic determinants of farmers non-compliance as well as the consequences of non-compliance on the performance of the carbon-offset market. Results support the standard finding that the extent of producers non-compliance decreases with an increase in the audit probability and/or an increase in the penalty per unit of non-compliance. In addition, the number of producers participating in the carbon offsets market is shown to increase with an increase in the carbon-offset price.<p> The analysis then introduces intermediaries in the market that will take care of trading carbon offsets as well as monitoring producers. The traders role in this study is played by an IOF (investor owned-firm) or a PA (producers association). Within the IOF, the analysis focuses on the monopoly and oligopoly structures. The key role of the traders is to guarantee, based on the amount of monitoring that is undertaken, that the emitters purchase only carbon offsets that actually correspond to sequestered carbon. The analysis then examines three cases for the group that monitors farmers compliance a group owned by for-profit traders, a government-run agency and a group owned by the PA trader. This part of the thesis examines what impact the involvement of the traders in the carbon-offset market has on non-compliance, as well as how the structure of the monitoring group affects non-compliance and the amount of carbon offsets traded in the market. The results of the analysis show that the monitoring groups always undertake sufficient monitoring to ensure that full compliance is achieved thus, while non-compliance is possible, it does not occur in equilibrium. The finding suggests that the formation of a government monitoring agency can potentially increase traded output and lower the price paid by emitters, still these changes are likely to be small, particularly when the trading sector is monopolistic. The overall analysis in this chapter shows that the optimal amount of enforcement, and as a result the cost effectiveness of a carbon-offset market, depends on the nature of the organization that undertakes the enforcement. <p>The next consideration of the thesis is the heterogeneity attributed to the timing of sequestration by different farmers. The analysis focuses on the carbon offsets pooling by considering two structures for the aggregator: a for-profit aggregator and a producers association. Pooling resources enables the farmers to benefit from economies of scale. The pricing schedule used by the aggregator is a two-part tariff. The two-part tariff is used as a way of providing an incentive for the farmers sequestering large amounts of carbon to participate in the pool. The study considers two alternatives for the coefficients that might be used to decide on the amount of carbon offsets to which each farmer will be entitled: default coefficient and custom coefficients. Each situation is modeled in a principal agent framework. <p>The analysis examines how the aggregator will target the monitoring service for different group of farmers. The investigation reveals that, under different scenarios, a PA or a FPA (for-profit aggregator) might lead to the formation of a heterogeneous pool or a homogeneous pool of each type. <p>The last issue investigated in this dissertation is the coexistence of a FPA and a PA in the default coefficient case. The analysis show that both aggregator structures can exist together in the market in the same time if the savings in the monitoring costs made possible by the PA are smaller than the cost of organizing the pool. If this condition is not satisfied the FPA cannot survive in the market and the producers association will dominate. <p>In addition to providing a better understanding of how the carbon-offset market may perform when introducing non-compliance, the results of this study can assist in assessing the cost effectiveness of the carbon-offset market when enforcement is undertaken by different organizations. Furthermore, the last consideration of the pooling option might help in selecting which type of pool a heterogeneous or a homogeneous one might perform better under different alternatives.
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Bioretention for Phosphorus Removal: Modelling Stormwater Quality ImprovementsROY-POIRIER, AUDREY 27 September 2009 (has links)
Bioretention systems are best management practices (BMPs) that make use of the biogeochemical processes within a forest-type ecosystem to provide at-source stormwater retention and pollutant removal. Laboratory studies and field monitoring have shown great potential for water quantity and quality control through the use of bioretention, but reported nutrient removal has been inconsistent between these systems. In particular, the processes involved in the cycling of phosphorus within bioretention systems are not clearly understood. Some studies report high phosphorus removal from bioretention systems, while phosphorus leaching was observed in other systems.
Phosphorus is a macronutrient required by all forms of life. It is also an important water pollutant, as it controls algal growth in most freshwater environments. High phosphorus loadings to these aquatic ecosystems can lead to eutrophication, which has significant ecological, environmental and economical impacts.
The Bioretention Phosphorus Removal Model (BPRM), an event-based one-dimensional finite difference model, was developed to simulate phosphorus removal in bioretention systems. The model includes four completely-mixed layers to simulate hydrologic processes as well as both soluble and particulate phosphorus transport in a bioretention system. Model processes include evapotranspiration, infiltration, overflow, exfiltration to native soils, underdrain discharge, soluble phosphorus sorption and vegetative uptake, and particulate phosphorus capture.
Monitoring data collected by the Toronto and Region Conservation Authority (TRCA) at a bioretention system installed on Seneca College’s King City campus, in Ontario, Canada, was used to evaluate the performance of BPRM. The model was found to overestimate total underdrain discharge volumes, but total phosphorus concentration and mass predictions were found to be useful for design purposes. BPRM correctly predicted phosphorus leaching from the Seneca College bioretention system for all storm events considered but one. The model can be used by practitioners to evaluate the potential for phosphorus leaching in a bioretention system.
A detailed sensitivity analysis revealed that BPRM phosphorus transport predictions are particularly sensitive to the drainage properties of bioretention soils, which highlights the importance of hydrologic transport processes for water quality control in bioretention systems. Modelling results suggested that soluble phosphorus desorption from bioretention soils was responsible for phosphorus leaching from the Seneca College bioretention system. / Thesis (Master, Civil Engineering) -- Queen's University, 2009-09-25 17:00:03.173
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