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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 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.
IDEM submitted its 2016 Integrated Report to U.S. EPA on April 1, 2016. The notice for the public comment period for the draft 2016 303(d) List of Impaired Waters was included with IDEM’s Integrated Report submittal and was published in the Indiana Register on April 6, 2016. IDEM will be accepting public comments on the draft 2016 303(d) list and the methodology used to develop it for a period of 90 days from April 6 to July 5, 2016. After the public comment period ends, IDEM will review and respond to the comments received. All public comments and IDEM’s responses will be submitted to U.S. EPA as an addendum to the 2016 Integrated Report and made available on this website. The links below contain all files included in IDEM’s April 1, 2016 Integrated Report submittal to U.S. EPA.
Indiana’s 2010 Integrated Water Monitoring and Assessment Report and earlier versions are available upon request by contacting IDEM’s Integrated Report Coordinator.