South Skunk River IA 03-SSK-931
from confluence with Indian Creek (S32 T80N R20W Jasper Co.) to outfall of Ames wastewater treatment plant in SW 1/4 S32 T83N R23W Story Co.
- Assessment Cycle
- 2024
- Release Status
- Final
- Data Collection Period
- Overall IR Category
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 11/1/2023 8:12:53 AM
- Updated
- 12/29/2023 10:33:04 AM
The Class A1 use was assessed as "not supported" due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class BWW2 use was assessed as "fully supported" based on biological sampling data and 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 10850002 South
Skunk River near Cambridge (DS1)
Iowa DNR 6 BIO See Below 286 South
Skunk River Cambridge 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 10850002 6 8/8/9 144 227 228 YES 4 / 3 6 / 3 5 / 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 10850002 6 36 / 3 7.3 8.5 8 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 10850002 6 Chloride 36 / 3 18 98 49 NA 0 / 0 7 NO Mon Full 10850002 6 Dissolved Oxygen 36 / 3 6.6 14.6 10.3 0 NA / NA 7 NO Mon Full 10850002 6 pH 36 / 3 7.3 8.5 8 0 NA / NA 7 NO Mon Full 10850002 6 Sulfate 36 / 3 18 95 55 0 NA / NA 7 NO Mon Full 10850002 6 Temperature 36 / 3 1 28.7 13.7 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 10850002 6 Ammonia 36 / 3 0.24 0.05 0.02 0 / 0 NO Mon Full 10850002 6 Cadmium 20 / 3 0.5 0.5 0.5 0 / 0 NO Mon Full 10850002 6 Chromium 20 / 3 2 0.75 0.69 0 / 0 NO Mon Full 10850002 6 Lead 20 / 3 1 0.92 1 0 / 0 NO Mon Full 10850002 6 Nickel 20 / 3 3.5 2.1 2 0 / 0 NO Mon Full 10850002 6 Selenium 18 / 2 4 1.5 1 0 / 0 NO Mon Full 10850002 6 Silver 20 / 3 1 0.902 1 0 / 0 NO Mon Full 10850002 6 Zinc 20 / 3 16 3.7 2.8 0 / 0 NO Mon Full Site ID Date Drainage Area (mi2) Ecoregion Major Drainage BM Sample Gear BMIBI score BMIBI Class 47b BMIBI BIT BMIBI Pass/Fail 286 7/23/20 605 47b MS Floating Art Sub 66 Good 62 Pass Community Assessment Type Assessment Result Support Level IR Category Reason Benthic
Macroinvertebrates Evaluated Pass (1/1) Full Assessment was
evaluated because the drainage area Overall Evaluated Pass Full 1 of the site was
greater than the calibrated range.
Class A1 - Indicator Bacteria:
Class A1 – pH:
Class BWW2 - Binomial Parameters:
Class BWW2 - Toxic Parameters:
Class BWW2 - Biological Sampling:
Benthic Macroinvertebrates:
Overall: