Using Ecological Risk Assessment Principles in a Source Water Protection Assessment

ABSTRACT

It has become increasingly common to apply ecological risk assessment (ERA) principles to watershed and regional scale environmental management. This article describes the application of watershed ERA principles to the development of a source water protection assessment and a strategic watershed management plan. The primary focus was on the protection of drinking water quality, a concern typically addressed by human health risk assessors. The approach emphasizes adaptations to the problem formulation phase of ERA (defining assessment endpoints, developing conceptual models and an analysis plan) suitable for watershed management planning in a multi-objective, multi-stressor context. Physical, chemical, and biological attributes were selected for primary drinking water quality assessment endpoints, and coupled with additional assessment endpoints relevant to other environmental and social management objectives. Conceptual models helped the planning team to better understand and communicate the multiple natural and human stressors in the watershed and the causal pathways by which they affected drinking water. The article provides an example of the types of adaptations that can make ERA principles suitable for watershed management related to human health goals, and illustrates the efficiency of integrating health and ecological assessments.

Keywords:

• watershed management
• ecological risk assessment
• source water protection
• drinking water quality.

ACKNOWLEDGMENTS

We thank Gordon Joyce, Stewart Irwin, Joel Ussery, and other members of the CRD Water Department who engaged in on-site review and discussions. Thanks to Bruce Blackwell for his participation and insights. We also thank Glenn Suter and Mike Slimak and anonymous reviewers for their helpful comments.

The views expressed in this article are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency, the Capital Regional District, or the consulting firms involved.