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Rule 13 requires that a SWQMP-Part B: Baseline Characterization SWQMP-Part B - State Form 51275 (available on the IDEM Agency Forms page) be submitted to IDEM within 180 days of the permittee's Notice of Intent (NOI) Letter submittal date (this date is provided to the MS4 Operator in the NOI letter Notice of Sufficiency mailed by IDEM). Part B is a summary of evaluations and conclusions and should document the information reviewed, the conclusions and recommendations based on the information reviewed, and, if additional information is needed, the plan for continuing to gather data. To help permittees complete a sufficient Part B, IDEM gave a presentation at the Indiana Association of Floodplain and Storm Water Managers (INAFSM) seminar on December 3, 2003, in Indianapolis. A PowerPoint slide presentation and resource list handout were provided at this seminar.

  • The Presentation [PDF] provides:
    1. a brief summary of the rule requirements as they relate to the Part B;
    2. IDEM's expectations of what information should, and should not, be included in a Part B;
    3. an introduction to IDEM's Assessment Information Management System (AIMS) database and the type of information available in this database; and
    4. a list of additional resources where existing water quality data can potentially be obtained.
    • The AIMS database contains information related to water chemistry, aquatic habitat, macroinvertebrate and fish communities, fish tissue analyses, sediments, and E. Coli bacteria. Some of the slides show actual data report pages (what someone making a request for data would receive), while other slides show the actual data entry pages in the database.
  • The Resource List Handout (Currently Unavailable) provides a list of potential water quality data informational sources, including IDEM, the Indiana Department of Natural Resources, U.S. Geological Survey, U.S. Army Corp of Engineers, U.S. Environmental Protection Agency, county Health Departments, county Soil and Water Conservation Districts, local industries, and local municipal wastewater treatment plants. This list is not comprehensive, and additional data may be available from other sources (e.g., universities). Also, for those permittees that have conducted a Stream Reach Characterization and Evaluation Report (SRCER) for compliance with the Combined Sewer Overflow (CSO) program, the submittal of the SRCER, by itself, is not sufficient to meet the Part B submittal requirements. SRCERs can be a valuable data resource, but it does not draw conclusions directly applicable to the separate storm sewer system.

During the process of requesting data, it may take some time to receive the information. In most cases, it will be beneficial to start the request process early to enhance the likelihood of receiving data in a timely manner. If, however, some of the resource data is not available in a timely manner, it is recommended that an on-going characterization plan be included with the Part B submittal. If the recommendation is followed, the plan would state that more existing data will be reviewed before all water quality conclusions are made, and, if known, describe how the previously unavailable data will be used to draw conclusions.

To interpret the potential data a permittee would receive, it is important to compare the chemical concentration values. Some values are easier to place acceptable values on (i.e., pH between 6.0 and 9.0 and dissolved oxygen above 4.0), but other values are more difficult (e.g., pesticides, metals, bacteria, nutrients, etc.). For the more difficult values, comparative analysis is the method IDEM would expect as a minimum (e.g., a stream segment has an elevated concentration of nitrates when compared to the other receiving waters in the MS4 area…one possible conclusion would be to target best management practices on nitrate reduction in the area of the elevated nitrate concentration).

In addition to chemical data, fish and macroinvertebrate community or habitat data could also be useful. Data for this information is typically related to specific indices. For fish communities, an Index of Biotic Integrity less than 35 indicates a non-supporting receiving water. For macroinvertebrate communities, a Macroinvertebrate Index of Biotic Integrity (using the Rapid Bioassessment Protocol) less than 4 indicates a non-supporting receiving water. For habitat data, a Qualitative Habitat Evaluation Index less than 51 indicates a non-supporting receiving water.

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