Improving the hydraulic performance of waste stabilization ponds (WSPs) is an important management strategy to not only ensure protection of public health and the environment, but also to maximize the potential reuse of valuable resources found in the treated effluent. To reuse effluent from WSPs, a better understanding of the factors that impact the hydraulic performance of the system is needed. One major factor determining the hydraulic performance of a WSP is sludge accumulation, which alters the volume of the pond. In this study, computational fluid dynamics (CFD) analysis was applied to investigate the impact of sludge layer geometry on hydraulic performance of a facultative pond, typically used in many small communities throughout the developing world. Four waste stabilization pond cases with different sludge volumes and distributions were investigated. Results indicate that sludge distribution and volume have a significant impact on wastewater treatment efficiency and capacity. Although treatment capacity is reduced with accumulation of sludge, the latter may induce a baffling effect which causes the flow to behave closer to that of plug flow reactor and thus increase treatment efficiency. In addition to sludge accumulation and distribution, the impact of water surface level is also investigated through two additional cases. Findings show that an increase in water level while keeping a constant flow rate can result in a significant decrease in the hydraulic performance by reducing the sludge baffling effect, suggesting a careful monitoring of sludge accumulation and water surface level in WSP systems.

This document includes three completed publications to represent Urban Agriculture as a ideal solution to meet the UN Sustainable Development Goals. The first publication (Weaver, 2017a) provided in Chapter Two examines the stormwater Best Management Practices (BMP) modelling parameters for the current EPA Stormwater Management Model (SWMM) as the first step to developing Urban Agriculture BMPs. The second publication (Weaver, 2015) provided in Chapter Three highlights how many high-rated scholars have identified agriculture as a critical driver for the planetary systems impacts we find with community development. The third publication (Weaver, 2017b) provided in Chapter Four breaks down a completely new definition for Urban Agriculture, as the foundational works disagree on meaning, resulting in an ambiguous definition. Together, these publications encourage engineers to model Sustainable Development options with green infrastructure (Weaver, 2017a), distinct from the Planetary Systems impacts of other contemporary options (Weaver, 2015), with a greater understanding of the social capital to engage stakeholders in meeting the UN Sustainable Development Goals (Weaver, 2017b).

Globally, the current state of freshwater resource management is insufficient and impeding the chance at a sustainable future. Human interference within the natural hydrologic cycle is becoming dangerously irreversible and the need to redefine resource managerial approaches is imminent. This research involves the development of a coupled natural-human freshwater resource supply model using a System Dynamics approach. The model was applied to two case studies, Somalia, Africa and the Phoenix Active Management Area in Arizona, USA. It is suggested that System Dynamic modeling would be an invaluable tool for achieving sustainable freshwater resource management in individual watersheds. Through a series of thought experiments, a thorough understanding of the systems’ dynamic behaviors is obtainable for freshwater resource managers and policy-makers to examine various courses of action for alleviating freshwater supply concerns. This thesis reviews the model, its development and an analysis of several thought experiments applied to the case studies.

Rainwater harvesting, the act of capturing and storing rain, is an ancient practice that is increasingly utilized today by communities to address water supply needs. This thesis examines whether domestic rainwater harvesting systems (DRWHS) can be a sustainable solution as defined by social, water quality, and technical feasibility for water security in semi-arid, rural environments. For this study, 50 surveys and 17 stored rainwater analyses were conducted in San Jose Xacxamayo, Mexico, in conjunction with my Peace Corps work of implementing 82 DRWHS. Results showed that all DRWHS were socially feasible because of cultural acceptance and local capacity. Water quality analyses showed that four DRWHS contained coliform bacteria; deeming water unfit for human consumption. Technical feasibility, examined through climate analyses, showed an average year-round reliability of 20-30% under current and future rainfall regime. The DRWHS can be a sustainable water supply option with roof expansion and treatment prior to consumption.

After the International Conference on Water and Environment in Dublin in 1992, the four socalled Dublin Principles created new managerial approaches for the water sector. This case study, which was conducted in the Limpopo Basin in Mozambique, examined the performance in the implementation of the principle related to “water development and management based on a participatory approach involving users, planners and policy makers at all levels”. The study was motivated by the fact that experience with the implementation of this principle in the Limpopo Basin of Mozambique has not delivered the anticipated outcomes. To this effect, this study analysed the history and performance of the decentralization process in the Limpopo Basin, and the factors that might have contributed to the outcomes we observe The methodology employed by the study was based on the framework for institutional analysis of decentralization reforms in natural resource management proposed by Dinar et al. (2005), Kemper et al. (2006), and Blomquist et al. (2008). This framework recommends that for the decentralization process to be successful, the following pre-requisites must be in place: (1) financial assistance from the state to enable basin level stakeholders to establish some of the organisations; (2) actors' participation and equitable representation of different segments of society, and acceptance of it from the communities; (3) the presence of basinlevel institutions, availability of forums for information sharing, communication and for conflict resolution; and (4) legitimacy, relevant human capacities and adequate financial resources among the River Basin Organizations (RBOs). The results from this study indicate that in as much as the Water Law, the Regulations of Water Services Provision and the Water Policy in Mozambique created the basis for the decentralization of water resources management, the operationalisation of the process has not been successful, considering that the prerequisites for an effective and sustainable decentralization process as postulated by Blomquist, Dinar and Kemper are still lacking. The study established that incentives for the decentralization process were not linked to the scarcity of water. The study further established that most prerequisites postulated by Blomquist, Dinar and Kemper were not satisfied, in particular: (1) the financial assistance from the state to enable basin level stakeholders to establish some of the organisations is inadequate; (2) the actors' participation and equitable representation of different segments of society with interest in water resources management is not satisfactory; and (3) the legitimacy, relevant human capacities and adequate financial resources for effective functioning of the Water Users Associations (WUAs) are still lacking. Copyright / Dissertation (MSc(Agric))--University of Pretoria, 2012. / Agricultural Economics, Extension and Rural Development / unrestricted

The Lake Kariba catchment area in southern Africa has one of the most variable climates of any major river basin, with an extreme range of conditions across the catchment and through time. The study characterized rainfall variability across the Lake Kariba catchment area, followed by describing prediction models for seasonal rainfall totals over the catchment and for inflows into Lake Kariba. The thesis therefore improved our understanding of rainfall variations over central southern Africa and provided evidence on how seasonal forecasts can be applied in order to potentially improve decision making in dam management. The prediction of the seasons in which floods or droughts are most likely to occur involves studying the characteristics of rainfall and inflows within these extreme seasons. The study started off by analyzing monthly rainfall data through statistical analysis. To determine the predictability of seasonal rainfall totals over the Lake Kariba catchment area, this study used low-level atmospheric circulation of a fully coupled ocean-atmosphere general circulation model over southern Africa, statistically downscaled to seasonal rainfall totals over the catchment. The verification of hindcasts showed that rainfall over the catchment is predictable at extended lead-times. Seasonal climate forecasts need to be integrated into application models in order to help with decision-making processes. The use of hydro-meteorological models may be proven effective for reservoir operations since accurate and reliable prediction of reservoir inflows can provide balanced solution to the problems faced by dam or reservoir managers. In order to reliably predict reservoir inflows for decision-making, the study investigated the use of a combination of physical and empirical models to predict seasonal inflows into the Lake. Two predictions systems were considered. First, antecedent seasonal rainfall totals over the upper Zambezi catchment were used as predictors in a statistical model for estimating seasonal inflows into Lake Kariba. The second and more sophisticated method used predicted low-level atmospheric circulation of a coupled ocean-atmosphere general circulation model downscaled to the inflows. Inflow hindcasts performed best during the austral mid-summer season of DJF (seasonal onset of inflows) and the autumn season of MAM (main inflow season). / Thesis (PhD)--University of Pretoria, 2015. / gm2015 / Geography, Geoinformatics and Meteorology / PhD / Unrestricted

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Groundwater seepage to surface water is an important process to peatland ecosystems; however, the processes controlling seepage zone distribution and magnitude are not well understood. This lack of process-based understanding makes degraded peatland ecosystems difficult to restore and problematic for resource managers developing a sustainable design. Degraded peatlands, particularly abandoned cranberry farms, often have drainage ditches, applied surface sand, and decreased stream sinuosity to artificially lower the water table and support agriculture. These modifications disconnect the surface and groundwater continuum, which decreases thermal buffering of surface water significantly. The combination of a decreased influx of thermally buffered groundwater, a naturally low surface gradient, minimal canopy, and strong solar input causes surface water temperature extremes that degrade ecosystem health. Through strategically incorporating the natural processes to restore groundwater discharge to restored surface streams, surface water temperature extremes will be buffered promoting a healthy, resilient wetland ecosystem. Therefore, it is critical to understand the spatial hydrogeologic constraints that induce groundwater seepage. Here we examine the spatial relationship between surficial groundwater seepage and the subsurface hydrogeologic structure within a mineraltrophic peatland environment. We use multiple field methods to develop a process-based conceptual model of the ground water seepage development at the site; these methods include geophysical, thermal, and isotopic techniques. The results indicate that there are two distinct forms of groundwater discharge to the peatland platform: diffuse lower-flux marginal seepage and discrete higher-flux interior seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, specifically when the basin slope is perpendicular to the regional groundwater gradient. These observations also allow insight into the formation of the groundwater discharge through time. The strong correlation between the subsurface basin structure and surficial groundwater expression will allow resource managers to more efficiently locate groundwater seepage on large, complex sites, and develop comprehensive management and restoration strategies for these critical ecosystems.

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No description available.