163-Analysis of Water Quality at Watershed-Scale and Equity Considerations in Pollution Control and Management .

Abstract

Proper management of water quality at watershed scale, especially due to non-point source pollutants, is of great importance where considerable revenue is generated to the local and national economies. Management of watersheds involves two important steps; first the accurate analysis of physical and other processes affecting flow, and fate and transport of pollutants of concerns, and second, the development of appropriate best management practices that can satisfy both environmental and stakeholder constraints. Significant work has been performed in the analysis of non-point source pollutants at watershed scale. Of the different methods, export coefficient approach has been popular in predicting the non-point source loadings to surface water pathways due to its simplicity and small data requirements. However, this approach has significant limitations because the method does not address hydrologic variability commonly present in all watersheds. In the control and management of non-point source pollutants, most best-management practices are developed with the focus of cost minimizations or cost efficiency with little regard to stake holder concerns especially in equity. Due to this limitation, implementation of proposed best-management practices to most large watersheds with multiple stakeholders and land use activities fail because cost equity is not considered in the development stages. In this work, we propose to address both these limitations in the analysis and management aspects of water quality. In the first step, we propose to modify the export coefficient method to include hydrologic variability and show that the results from the proposed approach have significantly better and reliable results over the classical export coefficient method. We further demonstrate the importance of considering both uncertainty and variability in the methodology using a Bayesian framework. In the second step, we will consider the tradeoffs between cost efficiency and cost equity in allocating pollution control responsibilities such that the framework can be adopted by decision-makers in a flexible manner. We show that cost efficiency and equity are important considerations in the management and the proposed methodology allows the decision-makers to develop a comprised solution based on environmental and stakeholder constraints.