Rock River IA 06-BSR-1534
mouth (S1 T95N R48W Sioux Co.) to confluence with Little Rock R. in S35 T98N R46W Lyon Co.
- Assessment Cycle
- 2024
- Release Status
- Pending
- Data Collection Period
- Overall IR Category
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Stable
- Created
- 11/1/2023 8:13:02 AM
- Updated
- 12/28/2023 1:37:34 PM
| Cycle Added | Class | Cause | Data Source | Rationale |
|---|---|---|---|---|
| 2020 | Class BWW1 | Metals: Selenium | Ambient monitoring: Iowa DNR-rivers | New data: WQ improvement (chemical / physical / bacterial) |
The Class A1 use remains assessed as "not supported" due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class BWW1 use was assessed as “WINOFI” based on biological sampling data. The Class HH use was assessed as "fully supported" based on water quality monitoring data.
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site
Name Site
Description Iowa DNR 6 WQ CY 2020-2022 10840001 Rock
River near Hawarden
Iowa DNR 6 BIO See Below 842 Rock
River Hawarden Site ID Data Source ID # Samples per Year (2020/ 2021/2022) 2020 Geometric Mean 2021 Geometric Mean 2022 Geometric Mean Violates Annual Geometric Mean? # 2020 SSM violations / SSM Violations needed for impairment # 2021 SSM violations / SSM Violations needed for impairment # 2022 SSM violations / SSM Violations needed for impairment Violates Annual SSM Significantly >10% Rule? Assessment Type Support Level 10840001 6 8/8/8 337 241 105 YES 4 / 3 2 / 3 2 / 3 YES Mon Not 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 10840001 6 36 / 3 7.4 8.7 8.2 0 7 NO Mon Full 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 10840001 6 Chloride 36 / 3 12 38 26 NA 0 / 0 7 NO Mon Full 10840001 6 Dissolved Oxygen 36 / 3 7.3 14.1 10.8 0 NA / NA 7 NO Mon Full 10840001 6 pH 36 / 3 7.4 8.7 8.2 0 NA / NA 7 NO Mon Full 10840001 6 Sulfate 36 / 3 30 120 87 0 NA / NA 7 NO Mon Full 10840001 6 Temperature 36 / 3 0 30.5 12.9 0 NA / NA 7 NO Mon Full Site ID Data Source ID Parameter Name # Samples / # Years Maximum Value Mean Value Median Value # Acute / Chronic Violations >1 Acute / Chronic Violation Assessment Type Support Level 10840001 6 Ammonia 36 / 3 0.87 0.07 0.02 0 / 0 NO Mon Full 10840001 6 Cadmium 20 / 3 0.5 0.5 0.5 0 / 0 NO Mon Full 10840001 6 Chromium 20 / 3 3 0.85 0.57 0 / 0 NO Mon Full 10840001 6 Lead 20 / 3 1 0.91 1 0 / 0 NO Mon Full 10840001 6 Nickel 20 / 3 4 1.8 1.6 0 / 0 NO Mon Full 10840001 6 Selenium 18 / 2 6 4 4 0 / 1 NO Mon Full 10840001 6 Silver 20 / 3 1 0.902 1 0 / 0 NO Mon Full 10840001 6 Zinc 20 / 3 3.2 1 0.5 0 / 0 NO Mon Full Site ID Date Drainage Area (mi2) Ecoregion Major Drainage BM Sample Gear BMIBI score BMIBI Class 47a BMIBI BIT BMIBI Pass/Fail 842 10/8/20 1680 47a MO Floating Art Sub 45 Fair 54 Fail Community Assessment Type Assessment Result Support Level IR Category Reason Benthic
Macroinvertebrates Evaluated Fail (0/1) WINOFI Assessment was evaluated because the
drainage area Overall Evaluated Fail WINOFI 3bu of the site was greater than the calibrated
range. Site ID Data Source ID Parameter Name # Samples / # Years Maximum Value Mean Value Median Value Number of Non - Detects Mean Value > Criterion or MCL Assessment Type Support Level 10840001 6 Selenium 18 / 2 6 4 4 0 NO Mon Full
Class A1 - Indicator Bacteria:
Class A1 – pH:
Class BWW1 - Binomial Parameters:
Class BWW1 - Toxic Parameters:
Class BWW1 - Biological Sampling:
Benthic Macroinvertebrates:
Overall:
Class HH-F - Toxic Parameters: