Scaling-up valued ecosystem components for use in watershed cumulative effects assessment

Abstract

The accumulating impacts from human development are threatening water quality and availability in the watersheds of Western Canada. While environmental impact assessment (EIA) is tasked with identifying such cumulative impacts, the practice is limited to individual projects, is not widely applied, overlooks activities occurring on the landscape, and fails to capture the effects of multiple projects over time. Limitations of the project-by-project approach are spurring the emergence of a regional framework for assessing aquatic cumulative effects within watershed boundaries. Watershed-based cumulative effects assessment (WCEA) will need a standard set of ecosystem components and indicators for assessment across the watershed, but it is not clear how such valued ecosystem components (VECs) and related measurable parameters should be identified. This study examined how aquatic VECs and indicators were used within project-based EIA in the South Saskatchewan River watershed and considered whether they could be scaled up for use in WCEA. A semi-quantitative analysis compared a hierarchy of assessment components and measurable parameters identified in the environmental impact statements of 28 federal screening, 5 federal comprehensive and 2 provincial environmental assessments from the South Saskatchewan River watershed, and examined factors affecting aquatic VEC selection. While provincial assessments were available online or at a central archive, federal assessments were difficult to access. Results showed that regulatory compliance was the dominant factor influencing VEC selection, followed by the preferences of government agencies with different mandates, and that provincial licensing arrangements interfered with VEC selection. The frequency of VECs and indicators used for aquatic assessment within EIA does not reflect the aquatic cumulative effect assessment (CEA) priorities for the watershed. The effective selection of VECs and indicators for aquatic cumulative effects assessment in practice requires both the implementation of WCEA and updating of guidelines for project-based EIA.