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Section 303(d) List of Impaired Waters

Every two years, 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 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 taking into account 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.

These requirements were met for the 2012, 2014, 2016, and 2018 cycles by IDEM’s submittal of its 303(d) lists for each of these cycles in their corresponding Integrated Reports. U.S. EPA issued a consolidated approval of all four 303(d) lists on May 9, 2019.

2018 303(d) List of Impaired Waters Approved by U.S. EPA

IDEM submitted its 2018 finalized 303(d) List of Impaired Waters to U.S. EPA on August 17, 2018. On May 9, 2019, U.S. EPA notified IDEM that it had consolidated its review of Indiana’s 2012, 2014, 2016, and 2018 303(d) lists.

In its approval letter, U.S. EPA concluded that IDEM has met the requirements of Section 303(d) of the federal Clean Water Act and all applicable requirements in the Code of Federal Regulations for all waters submitted on its 303(d) lists to date. However, U.S. EPA has deferred action on certain waters with regard to metals issues that U.S EPA and IDEM have yet to resolve.

The approved 2018 303(d) list (Category 5 of Indiana’s Consolidated Listing of All Waters) can be downloaded below:

Appendix I 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.

Indiana’s 2020 303(d) List of Impaired Waters

On January 29, 2020, IDEM published Indiana’s draft 2020 303(d) list and the Consolidated Assessment and Listing Methodology (CALM) in the Indiana Register for a 90-day public comment period, which ended on April 28, 2020. IDEM received no comments from the public during this time. IDEM presented the 2020 303(d) List of Impaired Waters to the Indiana Environmental Rules Board in a virtual public meeting on May July 8, 2020. On June 25, 2020, IDEM uploaded its 2020 Integrated Report, including its 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 and is presently working with U.S. EPA to facilitate its review.

Appendix L of the 2020 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:

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.

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