Date of Award

Spring 2003

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering - (Ph.D.)

Department

Civil and Environmental Engineering

First Advisor

Yuan Ding

Second Advisor

Paul C. Chan

Third Advisor

Fadi P. Deek

Fourth Advisor

Robert Dresnack

Fifth Advisor

John R. Schuring

Abstract

Recent public awareness of the environment has placed increased emphasis on the health and current state of the regional watershed. The watershed has been defined as that area in which water flowing across and beneath a given land surface drains into a specific stream or river, ultimately flowing through a single point or outlet on that stream or river. Since the processes involved are many and are analyzed in the literature on an individual basis, the current investigation attempts a more holistic approach by suggesting a methodology that integrates all elements of the hydrologic cycle. The investigation utilizes the area topography in the form of a digital elevation model (DEM) as the base for analysis.

Basic to any watershed model is a characterization of the water flow in streams by a mathematical function expressed through the hydrograph. The investigation explores the hydrograph and proposes that it can be constructed from hydrological components in a feedback concept with precipitation as input and the volume of flow as output. Feedback, for example, is represented as ground water and infiltration. An approach is presented to develop the watershed hydrograph from a Taylor series expansion using the derivatives of measured flow as parameters. The expansion result is transformed through LaPlace techniques into a representation of the hydrograph. Once done, the resulting time function can be transformed by the Fourier operator and a unique spectral signature of the stream obtained. It is further asserted that the national network of stream gages can be a useful source of data for this construct.

Included in the research is an investigation of the framework needed to package the information describing the watershed model. The Geographic Information System (GIS) is suggested as the ideal method to organize and provide clarity to the watershed model. Particularly important is the structured relational database required in this approach. Added to this are spatial geographic capabilities, which did not exist in the past.

Lastly, an investigation into the project management tasks necessary for the successful pursuit of a watershed-monitoring program is outlined. Emphasis here is placed on the inclusion of all the interested parties in the care taking of the watershed.

The analysis and modeling of watersheds are gaining increasing attention as managers and custodians become more acutely aware of the interactions of human activity and the environmental health of the watershed. Government investment in the streamgaging networks will contribute to this process by providing improved physical data to be used as input into the modeling efforts. The future holds greater promise to manage our natural resources through more comprehensive models of the environment.

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