Zhang, Yiwen (2014-06). Long-Term Changes in River System Water Budget in Texas. Master's Thesis. Thesis uri icon


  • Climate 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.

publication date

  • August 2014