Skunk River IA 03-SKU-889
mouth to confluence with Big Cr. southeast of Mt. Pleasant in S19 T70N R5W in Henry 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
- Unknown
- Created
- 11/1/2023 8:12:52 AM
- Updated
- 12/15/2023 1:39:13 PM
Assessment Summary
The Class A1 use was assessed as “not supported” due to levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class BWW1 use was assessed as "fully supported" based on biological sampling data and water quality monitoring data. The Class HH use was assessed as "fully supported" based on fish tissue sampling data and water quality monitoring data.
Assessment Explanation
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site
Name Site
Description Iowa DNR 6 WQ CY 2020-2022 10560002 Skunk
River near Augusta
USGS 11 WQ CY 2020-2020 5474000 Skunk
River at Augusta, IA
Iowa DNR 6 BIO See Below 943 Skunk River Augusta Iowa DNR 6 BIO See Below 1300 Skunk River New London (REMAP
#382) Iowa DNR 6 FT See Below 1169 Skunk River NE of Weaver 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 10560002 6 8/8/7 175 200 156 YES 4 / 3 2 / 3 1 / 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 10560002 6 36 / 3 7.3 8.6 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 10560002 6 Chloride 36 / 3 11 44 25 NA 0 / 0 7 NO Mon Full 10560002 6 Dissolved Oxygen 36 / 3 7 18.1 10.6 0 NA / NA 7 NO Mon Full 10560002 6 pH 36 / 3 7.3 8.6 8.2 0 NA / NA 7 NO Mon Full 10560002 6 Sulfate 36 / 3 11 68 37 0 NA / NA 7 NO Mon Full 10560002 6 Temperature 36 / 3 0 29.3 12.7 0 NA / NA 7 NO Mon Full 5474000 11 Temperature 902 / 3 -4 32 15 0 NA / NA 103 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 10560002 6 Ammonia 36 / 3 0.51 0.05 0.02 0 / 0 NO Mon Full 10560002 6 Cadmium 20 / 3 0.5 0.5 0.5 0 / 0 NO Mon Full 10560002 6 Chromium 20 / 3 3 0.91 0.52 0 / 0 NO Mon Full 10560002 6 Lead 20 / 3 1 0.9 1 0 / 0 NO Mon Full 10560002 6 Nickel 20 / 3 2.9 1.8 1.8 0 / 0 NO Mon Full 10560002 6 Selenium 18 / 2 2 0.9 0.5 0 / 0 NO Mon Full 10560002 6 Silver 20 / 3 1 0.902 1 0 / 0 NO Mon Full 10560002 6 Zinc 20 / 3 2.7 0.9 0.5 0 / 0 NO Mon Full BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/Thermal BM Sample Gear BMIBI score BMIBI Class 40a BMIBI BIT BMIBI Pass/Fail 1300 9/16/21 4230.0 40a MS/WW Floating ArtSub 56 Good 41 Pass 943 8/29/19 4303.0 40a MS/WW Hess 60 Good 41 Pass BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/Thermal Riffle Stream? FIBI score FIBI Class 40a FIBI BIT FIBI Pass/Fail 1300 9/16/21 4230.0 40a MS/WW NA 40 Fair 33 Pass Community Assessment Type Assessment Result Support Level IR Category Reason Benthic Macroinvertebrates Evaluated Pass (2/2) Full Fish Evaluated Pass (1/1) Full Assessment was evaluated because the
drainage area of the site Overall Evaluated Pass Full 1 used for the assessment was greater than the
calibrated range. Site ID Biopart Year Species # in sample / # of samples Avg Length (cm) (Avg) Hg (ppm) Chlordane (ppm) Sum PCBs (ppm) 1169 whole 2016 common carp 5 59.3 0.08 0.05 0.06 Support Level Full Class HH-F - Toxic Parameters: 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 10560002 6 Selenium 18 / 2 2 0.9 0.5 11 NO Mon Full
Class A1 - Indicator Bacteria:
Class A1 - pH
Class BWW1 - Binomial Parameters:
Class BWW1 - Toxic Parameters:
Class BWW1 - Biological Sampling:
Benthic Macroinvertebrates:
Fish:
Overall:
Class HH - Fish Tissue Sampling:
Assessment Key Dates
1/8/2020 | Monitoring Start |
12/16/2022 | Monitoring End |
8/29/2019 | Biological Monitoring |
9/14/2016 | Fish Tissue Monitoring |
9/16/2021 | Biological Monitoring |
Methods
200 | Physical/Chemical Monitoring |
315 | Regional reference site approach |
320 | Benthic macroinvertebrate surveys |
420 | Indicator bacteria monitoring |