Colorado Department of Transportation

Areawide Coordinated Cumulative Effects Assessment

The Areawide Coordinated Cumulative Effects Analysis (ACCEA) project evaluated whether and how a spatial accounting approach can be used to identify the cumulative impacts on the environment that result from the incremental impacts of multiple transportation and other projects, and related urbanization at a regional scale. Spatial accounting methods were employed to inventory improvement or decline in the quality of key resources over multiple time periods, jurisdictions and projects. The tools of spatial accounting include (1) data typically housed in a geographic information system (GIS); (2) models for the evaluation of environmental effects resulting from transportation projects and programs; and (3) metrics such as indicators or thresholds, which can be used to assess the importance of change in resource qualities.

The ACCEA project addressed a broad spectrum of environmental resources of concern, including land use and open space, and biological, water, cultural and community resources. Fourteen distinct resource areas were addressed during seven workshops held with resource experts representing transportation, environmental, and planning agencies and interest groups. A demonstration project was conducted which focused on land use change, habitat and water quality across the Denver metropolitan region. GIS and remote sensing tools were demonstrated to provide the means for data and models integration, thus providing a technical foundation for characterizing environmental effects. ACCEA was concluded to be feasible and can provide valuable support to both project-specific assessments of cumulative impacts as well as regional accounting of environmental resources relevant to transportation planning.

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