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Previous 303(d) Listings

2010 Impaired Waters List

Iowa DNR submitted its final 2010 Integrated Report, including Iowa's 2010 list of impaired waters, to U.S. EPA for approval on May 27, 2011.  Iowa DNR received final approval of the May 2011 submittal from U.S. EPA on June 29, 2011.

Public comments were sought on Iowa’s draft 2010 list from January 18, 2011 through April 4, 2011.  Comments were submitted to IDNR by one government agency (U.S. EPA) and two individuals.  Changes were made to the draft list based on the comments received.  Iowa's final 2010 Section 303(d) list, as submitted to U.S. EPA on May 27, 2011 for review and approval, contained 474 waterbodies with a total of 628 impairments. This version of the list was approved by U.S. EPA on June 29, 2011.

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 2010 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.  These guidelines suggest that states place all their waters (lakes, wetlands, streams, and rivers) into one of five general categories of their Integrated Report:

  • Category 1: All designated uses* are met.
  • Category 2: Some of the designated 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 total maximum daily load (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 of impaired waters.

Iowa’s 2010 Section 303(d) list (Category 5 of the Integrated Report) is the fifth 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 final 2010 list of waters in need of further investigation (WINOFI) contains 254 waterbodies. Iowa’s previous (2008) list of waters in need of further investigation contained 220 waterbodies. While 209 of the waterbodies from the 2008 WINOFI remain on Iowa’s 2010 “further investigation” list, 11 waterbodies were moved to other categories of the 2008 Integrated Report as follows:

  • TMDLs were prepared for two waters, and these waters were placed in Category 4a;
  • Nine waterbodies were assessed as “impaired” and in need of a TMDL and were placed in Category 5 (=Section 303(d) list).

The following materials comprise Iowa's final 2010 Integrated Report that was approved by U.S. EPA on June 29, 2011. The Section 303(d) list (Category 5) is the only EPA-approvable part of the Integrated Report.

2008 Impaired Waters List

Iowa DNR submitted its final 2008 Integrated Report, including Iowa's 2008 list of impaired waters, to U.S. EPA for approval on April 23, 2009. At EPA’s request, changes were made to the April 2009 submittal, and a revised Section 303(d) list and Integrated Report was submitted to U.S. EPA on April 28, 2010 for final approval. Iowa DNR received final approval of the April 2010 submittal on August 4, 2010.

Public comments were sought on Iowa’s draft 2008 list from December 10, 2008 through February 5, 2009. Four organizations responded with comments. None of the commenters proposed the addition of waterbodies to, or the removal of specific waterbodies from, Iowa’s draft 2008 Section 303(d) list.. Thus, Iowa's final 2008 Section 303(d) list, as submitted to U.S. EPA on April 23, 2009 for review and approval, contained 439 waterbodies. Based on discussions with U.S. EPA, the April 2009 submittal was revised and was re-submitted to U.S. EPA for approval on April 28, 2010. Changes made to the April 2009 version of the list included correction of errors and removal of impairments for which a TMDL had been approved by U.S. EPA. The revised (April 2010) version of Iowa’s 2008 Section 303(d) list contained 435 waterbodies with a total of 586 impairments. This version of the list was approved by U.S. EPA on August 4, 2010.

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 2008 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/2008_ir_memorandum.html.] These guidelines suggest that states place all their waters into one of five general categories of their Integrated Reports:
  • Category 1: All designated uses* are met.
  • Category 2: Some of the designated 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 total maximum daily load (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 of impaired waters.

Iowa’s 2008 Section 303(d) list (Category 5 of the Integrated Report) is the fourth 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 final 2008 list of waters in need of further investigation (WINOFI) contains 220 waterbodies including 156 river/stream segments, 28 lakes, and 36 wetlands. Iowa’s previous (2006) list of waters in need of further investigation contained 163 waterbodies. While 154 of the waterbodies from the 2006 WINOFI remain on Iowa’s 2008 “further investigation” list, 9 waterbodies were moved to other categories of the 2008 Integrated Report as follows:

  • two waterbodies were assessed with more recent data as “fully supporting” and were placed in Category 2 of the 2008 Integrated Report;
  • four 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);
  • three waterbodies were moved to Category 4c due to determination that the potential biological impairment was related to non-pollutant stressors including habitat alterations and hydrological modifications; thus, a TMDL was not required.

The following materials comprise Iowa's final 2008 Integrated Report that was approved by U.S. EPA on August 4, 2010. The Section 303(d) list (Category 5) is the only EPA-approvable part of the Integrated Report:

2006 Impaired Waters List

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.  At EPA’s request, changes were made to the October 2007 submittal, and a revised Section 303(d) list and Integrated Report was submitted to U.S. EPA on March 12, 2008 for final approval.  Iowa DNR received final approval of the March 2008 submittal on July 15, 2008. 

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, contained 282 waterbodies.  Based on discussions with U.S. EPA, the October 2007 submittal was revised and was re-submitted to U.S. EPA for approval on March 12, 2008.  Changes made to the October 2007 version of the list included correction of errors and removal of impairments for which a TMDL had been approved by U.S. EPA.  The revised (March 2008) version of Iowa’s 2006 Section 303(d) list contained 279 waterbodies with a total of 359 impairments; this version of the list was approved by U.S. EPA on July 14, 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 of impaired waters.

(*designated uses, as described in the Iowa Water Quality Standards, include Class A (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 final 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 of the 2006 Integrated Report;
  • 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 and on March 12, 2008 for review.  The Section 303(d) list (Category 5) is the only EPA-approvable part of the Integrated Report.

All water quality assessments for Iowa’s rivers, streams and lakes that have been developed to meet requirements of Sections 305(b) and 303(d) of the federal Clean Water Act can be found at Iowa DNR’s water quality assessment database, ADBNet.

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