Hecker Creek IA 01-YEL-447
mouth (T96N R06W Sec17 Allamakee Co.) to headwaters (Allamakee Co.)
- Cycle
- 2026
- Current Phase
- Public Comment
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Stable
- Created
- 10/27/2025 3:08:52 PM
- Updated
- 11/19/2025 3:16:37 PM
The presumptive Class A1 use was assessed as “not supported” due to levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The presumptive Class BWW1 use was assessed as “not supported” based on violations of Iowa’s aquatic life criteria for chloride and on biological sampling data. Note: A TMDL for the bacterial impairment for Yellow River basin streams was prepared by DNR in 2012 and was approved by U.S. EPA in February 2013. Due to TMDL completion, the Integrated Report category for the Class A1 recreational use was changed from 5p to 4a.
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site
Name Site
Description Iowa DNR 6 WQ CY 2024-2024 15030010 Hecker
Creek at Co. Rd. W48
Iowa DNR 6 WQ CY 2006-2008 15030010 Hecker
Creek at Co Rd W48 YRWP Iowa DNR 6 BIO See Below 158 Hecker
Creek Postville
Receiving Stream – W43 Bridge Presumptive Class A1 -
Indicator Bacteria: 2006-2008 Site ID Data Source ID # Samples / # Years 2006-2008 Geometric Mean Annual Geometric Mean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 15030010 6 49 / 3 2335 Yes 43 88% Yes Evaluated Not Presumptive Class A1 – pH: 2024 Site ID Data Source ID # Samples / # Years Minimum Value Maximum Value Mean Value # Violations Violations needed for impairment Violates Significantly >10% Rule? Assessment Type Support Level 15030010 6 5 / 1 8.1 9 8.4 0 2 NO EVALUATED NA Presumptive Class BWW1
- Chloride: 2006-2008 Site ID Data Source ID Parameter Name # Samples / # Years Maximum Value Mean Value Median Value # Acute / Chronic Violations % Acute/ Chronic Violations Significantly >10% Violations Assessment Type Support Level 15030010 6 Chloride 54 / 3 1500 437 340 16 / 24 30% / 44% Yes Evaluated Not Class BWW1 - Conventional Parameters: 2024 Site ID Data Source ID Parameter Name # Samples / # Years Minimum Value Maximum Value Mean Value # Violations # Acute / Chronic Violations Violations needed for impairment Violates Significantly >10% Rule? Assessment Type Support Level 15030010 6 Dissolved Oxygen 5 / 1 8.41 13.14 10.1 0 NA / NA 2 NO EVALUATED NA 15030010 6 pH 5 / 1 8.1 9 8.4 0 NA / NA 2 NO EVALUATED NA 15030010 6 Temperature 5 / 1 3.89 23.03 13.91 0 NA / NA 2 NO EVALUATED NA Presumptive Class BWW1 - Biological Sampling: Benthic Macroinvertebrates: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage BM Sample Gear BMIBI score BMIBI Class 52b BMIBI BIT BMIBI Pass/Fail 158 7/29/24 4.6 52b MS/WW Hess 62 Good 61 Pass 158 8/9/23 4.6 52b MS/WW Surber 67 Good 61 Pass BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage Riffle Stream? FIBI score FIBI Class 52b FIBI BIT FIBI Pass/Fail 158 7/29/24 4.6 52b MS/WW NA 18 Poor 52 Fail 158 8/9/23 4.6 52b MS/WW NA 84 Excellent 52 Pass
Community Assessment Type Assessment Result Support Level IR Category Reason Benthic Macroinvertebrates Monitored Pass (2/2) Full Fish Evaluated Fail (1/2) Not Assessment was evaluated because the fish assessment Overall Evaluated Fail Not 5bt was inconclusive.
Fish:
Overall: