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Integrated Water Monitoring and Assessment Report

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.

U.S. EPA reviewed Indiana’s 2020 303(d) list of Impaired Waters and issued a partial approval on February 19, 2021. In its partial approval, 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 determined that IDEM’s 303(d) list is not fully consistent with the requirements of Section 303(d) of the CWA and EPA’s implementing regulations based on IDEM’s decision to not list a number of waterbodies for certain metal pollutants.

U.S. EPA has issued a Public Notice for the waters it plans to add to Indiana’s 2020 List of Impaired Waters and will be accepting public comments on this issue through April 14, 2021. More information regarding U.S. EPA’s decision and instructions for how the public can submit comments directly to U.S. EPA during its public notice period can be found here:

A complete set of documents comprising U.S. EPA’s partial approval of Indiana’s 303(d) List of Impaired Waters is provided in the links at the bottom of this page.

IDEM’s 2020 Integrated Water Monitoring and Assessment Report Submittal, Including the 2020 303(d) List of Impaired Waters
U.S. EPA’s Partial Approval of Indiana’s 2020 303(d) List of Impaired Waters

Indiana’s 2018 Integrated Water Monitoring and Assessment Report and earlier versions are available upon request by contacting IDEM’s Integrated Report Coordinator.