Past Listings:

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.
 

• Final 2004 303(d) list (Category 5) (*.pdf)
• Final 2004 Section 303(d) EPA-approved Impaired Waters Map (*.pdf)
• Final 2004 EPA-approved Category 1 (*.pdf)
• Final 2004 EPA-approved Category 2a  (*.pdf)
• Final 2004 EPA-approved Category 2b (*.pdf)
• Final 2004 EPA-approved Category 3a  (*.pdf)
• Final 2004 EPA-approved Category 3b  (*.pdf)
• Final 2004 EPA-approved Category 4a  (*.pdf)
• Final 2004 EPA-approved Category 4b  (*.pdf)
• Final 2004 EPA-approved Category 4c  (*.pdf)
• Final 2004 EPA-approved Category 4d  (*.pdf)
• Final Methodology for the 2004 303(d) list (*.pdf)
• 2004 Responsiveness Summary (*.zip)
• Draft 2004 Database (*.zip)
  To use this database, you must have Microsoft Access 2000 or later installed.

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.

• Iowa's Final 2002 303(d) list, EPA Approved (*.pdf)
• 2002 Section 303(d) map (*.pdf)
• Final Methodology for the 2002 303(d) list (*.pdf)
• 2002 Final version of Waters In Need of Further Investigation under the Credible Data Law (*.pdf)
• Waterbody Specific Rationale for Removal (*.pdf)
• 2002 Responsiveness Summary (*.pdf)
• Iowa's 2002 303(d) list, Submitted to EPA for approval (*.pdf)
• Statement From Jeff Vonk On Iowa Impaired Waters List
• Draft 2002 List of Impaired Waters Narrative Summary (*.pdf)

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.

• Final Approved Iowa 1998 303(d) list of waters (PDF File)
• Map of Iowa's impaired waters
  • PDF File (1.4MB): More detail than gif File
  • gif File (157k): Smaller file, less detail
• Iowa 303(d) Waters Impacted by Phosphorus
  • Phosphorus Impacted Waters Map (PDF File)
  • Phosphorus Impacted Waters Map (GIF File)