Section 305(b) of the Clean Water Act (CWA) requires the Indiana Department of Environmental Management (IDEM) to assess and report on whether Indiana waters support the beneficial uses designated in Indiana’s water quality standards. IDEM’s CWA Section 305(b) assessments are made in accordance with IDEM’s Consolidated Assessment and Listing Methodology (CALM) by comparing existing and readily available water quality data to the applicable water quality criteria in the State’s water quality standards.
The large majority of the data IDEM uses in its 305(b) assessments are collected by IDEM staff using a rotating basin approach. IDEM has divided Indiana into nine major water management basins and monitors one major basin each year. IDEM staff assess the data collected in each basin the following year.
In addition to agency-collected data, IDEM solicits data through its External Data Framework from external organizations and agencies, including the United States Geological Survey, Indiana University’s School of Public and Environmental Affairs, and the Indiana State Department of Health. IDEM also solicits water quality data from other colleges, universities and local organizations, such as county health departments, watershed management groups and cities and towns.
IDEM’s water quality assessment results are reported to the United States Environmental Protection Agency (U.S. EPA) every two years through the Indiana Integrated Water Monitoring and Assessment Report, which describes the condition of Indiana’s lakes, streams, ground water and its Lake Michigan shoreline.
Indiana’s 2020 Integrated Water Monitoring And Assessment Report
IDEM published the notice of public comment period for its draft 2018 303(d) List of Impaired Waters, in the Indiana Register on January 29, 2020, formally opening the 90-day public comment period. IDEM received no comments on the draft 2020 303(d) list or the Consolidated Assessment and Listing Methodology (CALM) used to develop prior to the close of the public comment period on April 28, 2020. IDEM uploaded its 2020 Integrated Report, including the finalized 2020 303(d) List of Impaired Waters to U.S. EPA’s Assessment and Total Maximum Daily Load Tracking and Implementation System (ATTAINS) online on June 25, 2020 and is presently working with U.S. EPA to facilitate its review.
A complete set of documents comprising the 2020 Integrated Report is provided in the links below, fulfilling both CWA Sections 305(b) and 303(d) reporting requirements:
- Indiana's 2020 Integrated Water Monitoring and Assessment Report to the U.S. EPA (Revised) [PDF]
- Appendix A: Integrated Report Tables [PDF]
- Appendix B: Integrated Report Figures [PDF]
- Appendix C: Metadata and Definitions [PDF]
- Appendix D: Status of Category 4 Waters [PDF]
- Appendix E: IDEM’s Priority Ranking and 2018-2020-2022 Schedule for Total Maximum Daily Load Development [PDF]
- Appendix F: IDEM’s 305(b)/303(d) Monitoring, Assessment, Reporting, and Listing Schedule [PDF]
- Appendix G: IDEM’s 2018 Consolidated Assessment and Listing Methodology
- Appendix H: Comprehensive Aquatic Life Use and Recreational Use Assessments [PDF]
- Appendix I: Trend and Trophic Status of Indiana’s lakes
- Appendix J: IDEM’s Notice of Comment Period for the 2020 Draft 303(d) List (Narrative Only)
- Appendix K: IDEM’s Responses to U.S. EPA’s Comments on Indiana’s Draft 2020 303(d) List and Consolidated Assessment and Listing Methodology (CALM)
- Appendix L: Listing Tables Including Indiana’s Finalized 303(d) List of Impaired Waters (Category 5) for 2020
- Appendix M: Indiana’s 2020 Consolidated List (Categories 1-5)
Indiana’s 2018 Integrated Water Monitoring and Assessment Report and earlier versions are available upon request by contacting IDEM’s Integrated Report Coordinator.