US EPA

Increasingly, the regulatory, remedial and restoration actions taken to manage impaired environments are based on measurement and analysis of the state of the biotic community. When an aquatic community has been identified as impaired, the cause of the impairment must be determined so that appropriate actions can be taken. The Stressor Identification (SI) Guidance, published in December 2000, described a methodology for identifying the causes of observed impairments in aquatic systems.

Stressor identification requires extensive knowledge on a variety of stressors as well as depth of knowledge on the mechanism, symptoms, and stressor-response relationships for specific stressors. The goal of the Causal Analysis/Diagnosis Decision Information System (CADDIS) project is to support investigators in Regions, States and Tribes in the determination of causes of aquatic impairments. CADDIS is envisioned as a decision support system that will help investigators find, access, organize and share information useful for causal evaluations in aquatic systems.

At a workshop in Mt. Sterling, OH, August 26-28, 2002, representatives from the Office of Research and Development, Office of Water, EPA Regions, and States came together to conceptualize CADDIS and to identify critical research needs for system implementation and population. The plenary presentations from the workshop are provided here for viewing and download. These presentations summarize the history and vision for the project.

There was a clear consensus among workshop participants that CADDIS should be developed. Participants recommended that the system be developed incrementally and iteratively, and they emphasized that frequent user input and feedback will be essential to the system's success. Functions identified for short-term development include a step-by-step guide to SI, a knowledge base that would help users find and interpret relevant information, and assistance in organizing and reporting results.

The CADDIS Workshop Report, also available for download on this page, will be used as the basis of a strategic plan for system development and for more specific recommendations for the system's design, platform and architecture. By helping investigators identify the stressors responsible for effects, CADDIS will provide a critical step toward identifying sources, taking appropriate actions and improving the nation's environmental quality.

When an aquatic community has been identified as impaired, the cause of the impairment must be determined so that appropriate actions can be taken.