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Section 303(d) List of Impaired Waters

The IDEM Office of Water Quality (OWQ) develops Indiana's 303(d) List of Impaired Waters as part of the state's Integrated Water Monitoring and Assessment Report (IR), which is submitted to the U.S. EPA every two years in accordance with Sections 305(b) and 303(d) of the Clean Water Act (CWA).

CWA Section 305(b) requires states to make water quality assessments and provide water quality reports to the U.S. EPA, and CWA Section 303(d) requires states to identify waters through their Section 305(b) water quality assessments, that do not or are not expected to meet applicable state water quality standards with federal technology based standards alone. Under CWA Section 303(d), states are also required to develop a priority ranking for these waters considering the severity of the pollution and the designated uses of the waters. Once this listing and ranking of impaired waters is completed, states are required to develop Total Maximum Daily Loads (TMDLs) for these waters in order to achieve compliance with the water quality standards.

Indiana’s 2022 303(d) List of Impaired Waters

On January 14, 2022, IDEM published Indiana’s draft 2022 303(d) list and the Consolidated Assessment and Listing Methodology (CALM) on the IDEM Section 303(d) List webpage for a 45-day public comment period, which ended on February 28, 2022. A notice directing the public to the draft 2022 303(d) list and CALM was posted in the Indiana Register on January 26, 2022. IDEM received no comments from the public during this time.

IDEM presented the 2022 303(d) List of Impaired Waters to the Indiana Environmental Rules Board in a virtual public meeting on February 9, 2022.

On April 1, 2022, IDEM uploaded its 2022 Integrated Report, including its finalized 2022 303(d) List of Impaired Waters to U.S. EPA’s Assessment and Total Maximum Daily Load Tracking and Implementation System (ATTAINS) online.

Appendix L of the 2022 Integrated Water Monitoring and Assessment Report includes the 303(d) List (Category 5 of Indiana’s Consolidated List) and Category 4 waters, which are those that are impaired but do not require a Total Maximum Daily Load. Combined, these categories include all known impairments to Indiana waters:

The Listing Tables include the following information:

  • Category 5 of Indiana’s Consolidated Listing of All Waters (the 303(d) List)
  • Category 4 of Indiana’s Consolidated Listing of All Waters, which includes impaired waters that do not require a Total Maximum Daily Load (TMDL) under Section 303(d) of the Clean Water Act
  • The TMDL Key for the impairments identified in Category 4A
  • Change files for Categories 4 and 5, which describes all the changes made to these lists since IDEM’s 2020 303(d) list was approved.

General information on the 303(d) list is available on the Section 303(d) List Frequently Asked Questions page. You may also contact the Integrated Report Coordinator with any questions you have regarding the 303(d) list or to obtain files for previous listing cycles.

Public Comment Period Now Open for the Draft 2024 303(d) List of Impaired Waters

IDEM is now accepting public comments on the draft 2024 303(d) list and the Consolidated Assessment and Listing Methodology (CALM) used to develop it. The state-mandated, 45-day public comment period began on February 1, 2024 and will end on March 16, 2024.

After the public comment period closes, IDEM will review and develop responses to all comments received. IDEM will include the public comments and its responses to U.S. EPA as part of IDEM’s 2024 Integrated Report (IR), which will be submitted to U.S. EPA on April 1, 2024. General information on the 303(d) list is available on the Section 303(d) List Frequently Asked Questions webpage. You may also contact the Integrated Report Coordinator with any questions you have regarding the 303(d) list.

The 2024 303(d) List of Impaired Waters will be presented to the Indiana Environmental Rules Board in a public meeting on April 10, 2024, at 1:30 p.m., at the Indiana Government Center South, 10 North Senate Avenue, Conference Center Room A, Indianapolis, Indiana.

In the meantime, interested parties will find all the information they need to review and provide comment on the draft 2024 303(d) list and CALM in the links below. Attachments 3 through 8, which contain supporting tables, are provided in a spreadsheet format to provide the public the ability to more effectively search for information regarding specific waters of interest. Anyone experiencing difficulties accessing these tables can obtain a copy by contacting the Integrated Report Coordinator.

General information on the 303(d) list is available on the Section 303(d) List Frequently Asked Questions page. You may also contact the Integrated Report Coordinator with any questions regarding the 303(d) list.

  • Notice of Comment (NOC) Period for Indiana’s Draft 2024 303(d) List - NOC Narrative [PDF]
  • Draft 2024 303(d) Listing Tables Containing Supporting information for the Changes Identified in the Notice of Comment Period [XLS]
    • NOC Attachment 3: Waterbody Impairments Moved from Category 5 to Category 4A Based on Total Maximum Daily Load Development
    • NOC Attachment 4: Waterbody Impairments Removed from Category 5 Based on New or Revised Assessments Indicating Water Quality Improvements
    • NOC Attachment 5: Waterbody Impairments Removed from Category 5 as a Result of Ongoing Review to Ensure Accuracy in 303(d) Listing
    • NOC Attachment 6: Waterbody Impairments Added to Category 5 Based on New Assessments
    • NOC Attachment 7: Indiana’s Draft 2024 303(d) List of Impaired Waters – All Waterbodies (Category 5 of Indiana’s Consolidated Listing of All Waters)
    • NOC Attachment 8a: Impaired Waters that do not require a Total Maximum Daily Load (TMDL) Under Section 303(d) of the Clean Water Act (Category 4A of Indiana’s Consolidated Listing of All Waters)
    • NOC Attachment 8b: Impaired Waters that do not require a Total Maximum Daily Load (TMDL) Under Section 303(d) of the Clean Water Act (Category 4B of Indiana’s Consolidated Listing of All Waters)
    • NOC Attachment 8c: Impaired Waters that do not require a Total Maximum Daily Load (TMDL) Under Section 303(d) of the Clean Water Act (Category 4C of Indiana’s Consolidated Listing of All Waters)
    • NOC Attachment 8d: TMDL Key for Category 4A Waters Identified in Attachment 8a

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