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Iowa Geological Survey
109 Trowbridge Hall
Iowa City, IA 52242
(319) 335-1575


Iowa Section 303(d) Impaired Waters Listings

Iowa Stream (14K)

Under Section 303(d) of the Clean Water Act, states are required from "time to time" to submit a list of waters for which effluent limits will not be sufficient to meet all state water quality standards. EPA has defined "time to time" to mean April 1 of even numbered years. The failure to meet water quality standards might be due to an individual pollutant, multiple pollutants, "pollution," or an unknown cause of impairment. The 303(d) listing process includes waters impaired by point sources and nonpoint sources of pollutants. States must also establish a priority ranking for the listed waters, taking into account the severity of pollution and uses. The EPA regulations that govern 303(d) listing can be found in the Code of Federal Regulations 40 CFR 130.7.

The Iowa Department of Natural Resources TMDL and Water Quality Assessment Section compiles this impaired water list, or 303(d) listing. The 303(d) listing is composed of those lakes, wetlands, streams, rivers, and portions of rivers that do not meet all state water quality standards. These are considered "impaired waterbodies" and states are required to calculate total maximum daily loads (TMDLs) for pollutants causing impairments.

Current 303(d) Listing:
  • 2006 Impaired Waters List Submitted to EPA for approval
  • 2006 Impaired Waters List (DRAFT)
  • 2006 Impaired Waters Regional Lists and Maps
  • Understanding Iowa's Impaired Waters

    Past Listings:

  • 2004 Impaired Waters List
  • 2002 Impaired Waters List
  • 1998 Impaired Waters List

     


    Final 2006 Integrated Report and 303(d) list submitted to EPA for approval

    Iowa DNR submitted its final 2006 Integrated Report, including Iowa's 2006 list of impaired waters to U.S. EPA for approval on October 23, 2007. Public comments were sought on Iowa’s draft 2006 list from May 3 through June 29, 2007. Seven individuals or organizations, including U.S. EPA Region 7, responded with comments. As a result of these comments, one waterbody was removed and nine waterbodies were added to Iowa’s final list. Thus, Iowa's final 2006 Section 303(d) list, as submitted to U.S. EPA on October 23, 2007 for review and approval, contains 282 waterbodies. IDNR expects an approval/disapproval decision from U.S. EPA by early 2008.

    All states submit their Integrated Report and list of impaired waters every two years as required by Sections 305(b) and 303(d) of the Clean Water Act. Iowa’s 2006 Integrated Report was prepared according to U.S. EPA guidelines that combine (integrate) requirements of Sections 305(b), 303(d), and 314 of the federal Clean Water Act [see http://www.epa.gov/owow/tmdl/2006IRG/]. These guidelines suggest that states place all their waters into one of five categories of their Integrated Reports:

    • Category 1: All designated uses are met.

    • Category 2: Some of the uses are met but insufficient information exists to determine whether the remaining uses are met.

    • Category 3: Insufficient information exists to determine whether any uses are met.

     • Category 4: The waterbody is impaired but a TMDL is not required.

    • Category 5: The waterbody is impaired and a total maximum daily load (TMDL) is needed.  Category 5 is the state’s Section 303(d) list.

    (*designated uses, as described in the Iowa Water Quality Standards, include Class A (primary contact recreation) uses, Class B (aquatic life) uses, and Class C (drinking water) uses.  Any Iowa waterbody can be designated for one or a combination of these three types of beneficial use.)

    Iowa’s 2006 Section 303(d) list (Category 5 of the Integrated Report) is the third such list to be developed under Iowa’s Credible Data Law. This law, passed by the Iowa Legislature in 2000, requires that listing decisions be based on scientifically valid chemical, physical, or biological data collected under a scientifically accepted sampling and analysis plan, including quality control and quality assurance procedures. The Department believes this “credible data” law has been implemented in conjunction with the federal listing requirements such that all readily available and existing water quality related data and information have been used for list development.

    As provided for in Iowa's credible data law, the Department is to maintain a separate list of waters that require further investigative monitoring. As specified in the credible data law, this list is not part of the Section 303(d) process in Iowa and includes waterbodies where limited information suggests, but does not conclusively (credibly) demonstrate, that a water quality impairment exists. If the results of further investigative monitoring demonstrate, with data of sufficient quality and quantity, that a water quality impairment exists, the affected waterbody can be added to Iowa's Section 303(d) list. Iowa's 2006 list of waters in need of further investigation (WINOFI) contains 139 waterbodies including 93 river/stream segments, 9 lakes, and 37 wetlands. Iowa’s 2004 list of waters in need of further investigation contained 101 waterbodies. While 78 of these waterbodies remain on Iowa’s 2006 “further investigation” list, the remainder of the 101 waterbodies were moved to other categories of the 2006 Integrated Report as follows:

    • eight waterbodies were assessed with more recent data as “fully supporting” and were placed in Categories 1 or 2;

    • three waterbodies with approved TMDLs were moved to Category 4a;

    • five waterbodies were assessed with more recent data as “impaired” and in need of a TMDL and were placed in Category 5 (=Section 303(d) list);

    • six waterbodies were assessed as “fully supporting” for the 2006 reporting/listing cycle and moved to Categories 1 or 2 due to changes or updates in IDNR’s assessment methodology (for example, (1) the EPA-recommended elimination of the “fully supported/threatened” assessment category and (2) the update of IDNR’s biological impairment criteria);

    • one waterbody was removed due to an error in the 2004 assessment.

    The following materials comprise Iowa's final 2006 Integrated Report that were submitted to U.S. EPA on October 23, 2007 for their approval:

     


    Draft 2006 Impaired Waters List

    Request for public comments: Iowa DNR has prepared a draft 2006 list of impaired waters as required by Section 303(d) of the federal Clean Water Act. Iowa DNR is now seeking public comments on this draft list. Public comments will be solicited from May 1 through June 29, 2007. Following the end of the public comment period, the draft list will be modified based on the comments received, and the list will be forwarded to U.S. EPA for their review and approval or disapproval.

    Please mail comments to:

    Iowa Department of Natural Resources
    Attention: John Olson
    Watershed Monitoring & Assessment Section
    Wallace State Office Building
    502 East 9th Street
    Des Moines, IA 50319
     

    Comments can also be e-mailed to the following address: john.olson@dnr.state.ia.us.

    Iowa’s draft 2006 Section 303(d) list of impaired waters was prepared according to U.S. EPA guidelines for “integrated reporting” that combines requirements of Sections 305(b), 303(d), and 314 of the federal Clean Water Act (see http://www.epa.gov/owow/tmdl/2006IRG/. These guidelines suggest that states place all their waters into one of five categories of their Integrated Report:

    • Category 1: All designated uses are met.

    • Category 2: Some of the uses are met but insufficient information exists to determine whether the remaining uses are met.

    • Category 3: Insufficient information exists to determine whether any uses are met.

     • Category 4: The waterbody is impaired but a TMDL is not required.

    • Category 5: The waterbody is impaired and a total maximum daily load (TMDL) is needed (i.e., the state’s Section 303(d) list).

     Iowa’s 2006 Section 303(d) list is the third to be developed under Iowa’s Credible Data Law. This law requires that listing decisions be based on scientifically valid chemical, physical, or biological data collected under a scientifically accepted sampling and analysis plan, including quality control and quality assurance procedures. The Department believes this “credible data” law has been implemented in conjunction with the federal listing requirements such that all readily available and existing water quality related data and information have been used for list development.

    Iowa's draft 2006 Section 303(d) list (Category 5 of the Integrated Report) contains 274 waterbodies with a total of 356 impairments Of these impairments, 158 impairments are new to the impaired waters list and are based primarily on new monitoring data.

    As provided for in Iowa's credible data law, the Department is to maintain a separate list of waters that require further investigative monitoring. As specified in the credible data law, this list is not part of the Section 303(d) process in Iowa and includes waterbodies where limited information suggests, but does not conclusively (credibly) demonstrate, a water quality impairment. If the results of further investigative monitoring demonstrate, with data of sufficient quality and quantity, that a water quality impairment exists, the affected waterbody can be added to Iowa's Section 303(d) list. Iowa's draft 2006 list of waters in need of further investigation contains 175 waterbodies including 128 river/stream segments, 10 lakes, and 37 wetlands. Iowa’s 2004 list of waters in need of further investigation contained 101 waterbodies. While 76 of these waterbodies remain on Iowa’s draft 2006 “further investigation” list, 24 waterbodies on the 2004 WINOFI list were moved to other categories of the draft 2006 Integrated Report as follows:

    • 13 waters were assessed as “fully supporting” and were placed in IR Categories 1 or 2;

    • 1 waterbody is now considered “not assessed” because more than six years have elapsed since occurrence of the fish kill that led to impairment

    • 3 waterbodies were assessed as “impaired” but the impairment does not require preparation and approval of a TMDL; these waterbodies were placed in Category 4;

    • 7 waterbodies were assessed as “impaired” and in need of a TMDL and were placed in Category 5 (=Section 303(d) list).

    The following materials are presented for review:

     


    2004 Impaired Waters List

    Iowa’s 2004 Section 303(d) list of impaired waters was prepared according to U.S. EPA guidelines for “integrated reporting” that combines requirements of Sections 305(b), 303(d), and 314 of the federal Clean Water Act. These guidelines suggest that states place all their waters into one of five categories of their 2004 Integrated Report:
    • Category 1: All designated uses are met.
    • Category 2: Some of the uses are met but insufficient information exists to determine whether the remaining uses are met.
    • Category 3: Insufficient information exists to determine whether any uses are met.
    • Category 4: The waterbody is impaired but a TMDL is not required.
    • Category 5: The waterbody is impaired and a total maximum daily load (TMDL) is needed (i.e., the state’s Section 303(d) list).

    Iowa’s 2004 Section 303(d) list is the second to be developed under Iowa’s Credible Data Law. This law requires that listing decisions be based on scientifically valid chemical, physical, or biological data collected under a scientifically accepted sampling and analysis plan, including quality control and quality assurance procedures. The Department believes this “credible data” law has been implemented in conjunction with the federal listing requirements such that all readily available and existing water quality related data and information have been used for list development.
    Public comments were sought on Iowa’s draft 2004 list from February 21 through April 15, 2005. The public comment period was initially set to end on April 1st but was extended to allow the public more time to review the list. Comments were received from six individuals and organizations.

    Iowa's 2004 Section 303(d) list with 209 waterbodies was submitted to the Environmental Protection Agency (EPA) on May 26, 2005 for review and approval. Based on their review, EPA partially approved and partially disapproved Iowa's submitted 303(d) list in November 2005. As part of their decision, EPA proposed to add back 20 waterbodies and associated pollutants of concern to Iowa's 2004 list of impaired waters that Iowa had not included on their May 2005 list. EPA took public comments on their decision from November 18 to December 19, 2005.

    Based on public comments received and on EPA’s further review, Iowa received its final/approved 2004 Section 303(d) list of impaired waters from EPA on May 23, 2006. Of the 20 water bodies proposed for listing by EPA, 17 were included on Iowa's final 2004 list. Iowa's final-approved 2004 Section 303(d) list contained 225 waterbodies. EPA also approved the removal of 43 waterbodies from Iowa’s 2002 Section 303(d) list for the following reasons: TMDLs for 12 waterbodies were developed by IDNR and approved by EPA; new data for 13 waterbodies supported removal from the Section 303(d) list, flaws in the original assessment resulted in removal of 12 waterbodies, and changes in the IDNR waterbody identification numbers for six waterbodies required their removal from the 2004 Section 303(d) list (these six waterbodies, however, remain (with new identification numbers) on Iowa’s 2004 Section 303(d) list (Category 5)).

    As provided for in Iowa's credible data law, the Department is to maintain a separate list of waters that require further investigative monitoring. As specified in the credible data law, this list is not part of the Section 303(d) process in Iowa and includes waterbodies where limited information suggests, but does not conclusively (credibly) demonstrate, a water quality impairment. If the results of further investigative monitoring demonstrate, with data of sufficient quality and quantity, that a water quality impairment exists, the affected waterbody can be added to Iowa's Section 303(d) list. Iowa's 2004 list of waters in need of further investigation contains 101 waterbodies including 53 river/stream segments, 12 lakes, and 36 wetlands. Iowa’s 2002 list of waters in need of further investigation contained 170 waterbodies. While 65 of these waterbodies remain on Iowa’s 2004 “further investigation” list, the remainder of the 170 waterbodies were moved to other categories of the 2004 Integrated Report as follows:

    • 18 waters were assessed as “fully supporting” and were placed in Categories 1 or 2;
    • 37 waterbodies were assessed as “impaired” but the impairment does not require preparation of a TMDL; these waterbodies were placed in Category 4;
    • 50 waterbodies were assessed as “impaired” and in need of a TMDL and were placed in Category 5 (=Section 303(d) list).

    The removal of these 105 waterbodies from Iowa’s “further investigation” list resulted either from the existence of new water quality data or from a change in IDNR’s assessment methodology.
     



    2002 Impaired Waters List

    The State of Iowa has identified 188 waterbodies for the 2002 Impaired Waters List.

    Iowa’s 2002 Section 303(d) list is the first to be developed under a new state law passed by the Iowa Legislature in 2000. This law requires that listing decisions be based on scientifically valid chemical, physical, or biological data collected under a scientifically accepted sampling and analysis plan, including quality control and quality assurance procedures. The Department believes this “credible data” law can be implemented in conjunction with the federal listing requirements to use all readily available and existing water quality related data and information.

    Public comments were sought on the list from August 19th through November 1, 2002. The public comment period was initially set to end on September 19th, but was extended to allow the public more time to review the list. Comments were received from approximately 30 individuals and organizations.

    Iowa's 2002 Section 303(d) list was submitted to the Environmental Protection Agency on December 18th, 2002 for review and approval. On July 11, 2003, EPA partially approved and partially disapproved Iowa's submitted 303(d) list. EPA proposed to add back 20 water bodies and associated pollutants of concern to Iowa's 2002 list of impaired waters that Iowa had not included on the list. Of the 20 water bodies proposed for listing by EPA, 18 are included on Iowa's final 2002 list. EPA also approved Iowa's listing of 136 water bodies and delisting of 71 water bodies.

    Iowa's Final 2002 Section 303(d) list contains 205 waterbodies and 286 impairments.

    As provided for in Iowa's credible data law, the Department is to maintain a separate list of waters that require further investigative monitoring. As specified in the credible data law, this list is not part of the Section 303(d) process in Iowa and includes waterbodies where limited information suggests, but does not conclusively (credibly) demonstrate, a water quality impairment. If the results of further investigative monitoring demonstrate, with data of sufficient quality and quantity, that a water quality impairment exists, the affected waterbody can be added to Iowa's Section 303(d) list. Iowa's 2002 list of waters in need of further investigation contains 171 waterbodies including 108 river/stream segments, 23 lakes, and 40 wetlands.

     


    1998 Impaired Waters List

    The Iowa Department of Natural Resources has identified 157 waters in the state for which existing required pollution controls are not stringent enough to implement state water quality standards. The Federal Clean Water Act Section 303(d) requires that each state establish a list of these waters, and the 1998 list is available. The state is required to establish total maximum daily loads (TMDLs) for waters on the list according to priority ranking. This list was originally published as a draft, subjected to public comment and revised prior to adoption.

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    Iowa Geological Survey     109 Trowbridge Hall     Iowa City, IA 52242-1319     Phone: 1-319-335-1575     Fax: 1-319-335-2754