Browsing by Subject "Water Management"
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Item A Systems-Integration Approach to the Optimal Design and Operation of Macroscopic Water Desalination and Supply Networks(2012-02-14) Atilhan, SelmaWith the escalating levels of water demand, there is a need for expansion in the capacity of water desalination infrastructure and for better management and distribution of water resources. This dissertation introduces a systems approach to the optimization of macroscopic water desalination and distribution networks to tackle three problems: 1. Optimal design of desalination and allocation networks for a given demand, 2. Optimal operation of an existing infrastructure of water desalination, distribution, and storage, 3.Optimal planning for expanding the capacity of desalination plants to meet an increasing water demand over a time horizon. A source-interception-sink representation was developed to embed potential configurations of interest. Mathematical programming was used to model the problem by studying different objective functions while accounting for constraints the supply, demand, mass conservation, technical performance, and economic aspects. Such approach determines the type of technologies to be selected, the location and capacity of the desalination plants, and the distribution of the desalinated water from sources to destinations. For the operation and planning problems, the planning horizon was discretized into periods and a multi-period optimization approach was adopted with decisions made for each period. Short- and long-term water storage options (e.g., in storage tanks, aquifers) were included in the optimization approach. Water recycle/reuse was enhanced via the use of treated water and its utilization was improved by minimizing the losses observed in discharged water resulting from the linkage of power plants and thermal desalination plants and the lack of integration between water production and consumption. Several case studies were solved to demonstrate the applicability of the devised approaches.Item Long-Term Changes in River System Water Budget in Texas(2014-06-27) Zhang, YiwenClimate change and water resources development are recognized as the two key factors that change long-term water budget, flow-frequency, and storage-frequency characteristics of different river systems. However, quantifying long-term changes is difficult due to the great natural variations in flows that hide long-term trends. This thesis investigates the relative impacts of various factors on long-term changes in river flows, reservoir storage, evaporation volumes, water use, and other components of river system water budgets in different regions of Texas to develop a better understanding of changes in river system hydrology. The beginning part of this research includes a literature review based assessment of quantifying the impacts of urbanization, agricultural practices, dams and reservoirs, human water use, and climate change on stream flow. The literature review assessment provides an overview of past studies of quantifying the impacts of stream flow studies performed using either statistical trend analyses of gauged stream flow data or watershed precipitation-runoff simulation models. The overview provides a summary on the variable effects of human activities and climate change on stream flow trends. The thesis research is based on using the Texas Commission on Environmental Quality (TCEQ) modeling system and Texas Water Development Board (TWDB) databases to explore the relative effects of climate change, water resources development, water use, and other factors on long-term changes in river flow, reservoir storage, evaporation, water use, and other components of the water budgets of different river basins of Texas. Observed stream flow at 31 gaging stations showed an upward trend in stream flow at 14 stations and downward trend at 17 stations, most of them in the west Texas, during the simulation period. Long-term precipitation and reservoir surface evaporation trends in Texas are minimal, therefore, compared with climate change, human activity plays a major role on water budget change.