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Nonpoint Source Water Pollution

Nonpoint Source > Watershed Assessment > Impaired Waters - Integrated Report Impaired Waters - Integrated Report

The Indiana Department of Environmental Management (IDEM) develops the Integrated Water Monitoring and Assessment Report every two years to fulfill the requirements of Sections 305(b) and 303(d) of the federal Clean Water Act (CWA). The Integrated Report is submitted to U.S. EPA in even-numbered years.

Section 305(b) requires IDEM to assess and report on whether Indiana waters support the beneficial uses designated in the Indiana’s water quality standards. These 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.

Section 303(d) requires states to identify waters that are assessed as not meeting applicable water quality standards, also known as impaired, or for which one or more designated uses are threatened.

The Integrated Report includes the Consolidated List which places each of Indiana’s waterbodies into one or more categories. The category a waterbody falls under depends on what is known about the water quality:

  • Category 1: The waterbody is fully supporting all of its designated uses and none of its uses are threatened.
  • Category 2: The waterbody is fully supporting the designated use assessed and no other use is threatened; insufficient data and information are available to determine if the remaining uses are supported or threatened.
  • Category 3: Insufficient data and information are available to determine if the waterbody is supporting its designated use.
  • Category 4: The designated use is impaired or threatened but a total maximum daily load (TMDL) is not required because:
    1. A TMDL has already been completed for the impairment(s) and approved by U.S. EPA and is expected to result in attainment of all applicable water quality standards;
    2. Other pollution control requirements are reasonably expected to result in the attainment of the water quality standard in a reasonable period of time; and/or,
    3. Impairment is not caused by a pollutant.
  • Category 5: The designated use is impaired, and a TMDL is required because:
    1. The aquatic life use, recreational use, or drinking water use is impaired or threatened by one or more pollutant;
    2. The “fishable use” of the waterbody is impaired; and/or,
    3. The concentration of mercury or PCBs in the edible tissue of fish collected from the waterbody exceeds Indiana’s human health criteria for these contaminants.

The 303(d) list is comprised of the Category 5 waters on Indiana’s Consolidated List and is included in Appendix A of the Integrated Report.

Electronic Services

  • Impaired Waters (e303d): This web-GIS application provides a display of the impaired waters along with additional information associated with the listings, such as the development status of TMDLs and the establishment of watershed management plans (WMPs). This application offers users the ability to zoom to their address, water body, county, or watershed, identify waterbodies and all associated listing category data, TMDLs and WMPs where these activities are or have been occurring in the selected area, and provides the assessments reported in the Integrated Report. You may also skip the tutorial page.

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