Author

Xiaobing Zhao

Date of Graduation

2004

Document Type

Thesis

Abstract

Most water management studies concentrate on the inter-temporal allocation problem or, more recently, spatial dynamics—but not both. While early spatial-temporal studies focused on the allocation of water quantity, this paper presents an approach to water quality analysis that incorporates both spatial and temporal dynamics in a watershed framework. The model developed is an explicit economic watershed optimization model built upon an underlying water quality model where pollution loads are driven by pollution sources and alternative control strategies. It reflects the spatial aspects of pollution loads and treatment and the way the system reacts over time to management options and natural forces. The acid mine drainage (AMD) problem in the Cheat River watershed of West Virginia serves as a case study and provides an opportunity to test the modeling approach developed. Three subwatersheds—Muddy Creek, Little Sandy Creek, and the Albright Region subwatersheds—are selected to conduct the empirical analyses. The empirical models are written in General Algebraic Modeling System (GAMS) and solved using the CPLEX mixed integer programming package. The results give spatial and temporal distributions of optimal AMD treatment investments, annual levels of AMD treatment by segment, and estimates of acid loadings and ecological services. The results suggest that available investments should be concentrated in heavily impaired stream segments. The optimal temporal and spatial investment strategies are manipulated to assess the economic and ecological implications of water quality trading in the Cheat River watershed. Such trading could involve point and nonpoint sources and both same pollutant and cross pollutant trading. The trading scenarios show that appropriate trades between point and nonpoint sources yield substantial benefits. While net increases in the ecological index are not achieved until water quality reaches the threshold level necessary to support higher ecological services, the additive effect of improvements in multiple stream segments favors upstream trading but does not preclude other possibilities. While the application is specific to the AMD related water quality problems important in the Cheat River watershed, the approach provides insight into the usefulness of economic analysis in Total Maximum Daily Load (TMDL) implementation and other watershed management issues.

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