Planning Sections

Causal Assessment Project for San Diego Creek

Biologically based assessments (bioassessments) of stream health are becoming the foremost approach to evaluate the condition of California's perennial stream ecosystems.  When the biology of a stream is found to be degraded, the cause(s) of the problem needs to be identified to inform corrective measures or other management actions.

Causal assessment is the diagnoses of the stressor(s) leading to degraded biology. The U.S. EPA has developed a causal assessment framework for use in stream environments: the Causal Assessment Diagnosis and Decision Information System (CADDIS).

The San Diego Creek Causal Assessment Project implemented CADDIS, with modifications, to assess the cause of poor benthic macroinvertebrate community conditions in a subreach of San Diego Creek.  The project was conducted by Regional Board staff in partnership with the Southern California Coastal Water Research Project (SCCWRP) and additional local stakeholders.

Final Project Report (November 25, 2019)


The following documents are available on request. To request a copy, please contact Doug Shibberu at (951) 782-7959.

    • Appendix A:  Conceptual Models for the Candidate Causes
    • Appendix B1:  Co-occurrence Line of Evidence
      • Spatial Temporal Co Occurrence LOE Spreadsheet
    • Appendix B2:  Stressor-Response from Local Comparators Line of Evidence
      • Stressor Response from Local Comparators LOE Spreadsheet
      • Spearman Correlation Plots
    • Appendix B3:  Stressor-Response from Regional Comparators Line of Evidence
    • Appendix B4:  Reference Comparison Line of Evidence
    • Appendix B5:  Stressor-Response from the Lab Line of Evidence
    • Appendix B6:  Lab Tests of Site Media Line of Evidence
    • Appendix C:  Pesticide Use Data Assessment
    • Appendix D: Cross-tabulated Taxa Counts from Bioassessments conducted in the Newport Bay & Santiago Creek Watersheds
    • Appendix E:  Multisite Approach