Iowa River IA 02-IOW-627
from confluence with English R. (Washington Co.) to Burlington Street Dam in Iowa City (Johnson Co.)
- Cycle
- 2024
- Release Status
- Final
- Overall IR
- 4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
- Trend
- Unknown
- Created
- 11/1/2023 8:12:47 AM
- Updated
- 2/2/2024 10:26:47 AM
The Class A1 use was assessed as "not supported" based on indicator bacteria monitoring data. The Class BWW1 use was assessed as “WINOFI” based on biological sampling data. The Class HH use was assessed as "fully supported" based on fish tissue sampling data. Note: A TMDL covering the bacteria impairments for all segments, with the segment code prefix "IA 02-IOW" in the Iowa River Basin, was approved by EPA in 2018. Due to the completion of the TMDL, the IR category for the Class A1 use was changed from 5a (impaired; TMDL needed) to 4a (impaired; TMDL approved).
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 WQ CY 2010-2012, CY 2012-2014 10520003 Iowa River Downstream of Iowa City (DS1) County Road F62 bridge E of Hills Iowa DNR 6 BIO See Below 940 Iowa River Iowa City – DS1 Iowa DNR 6 FT See Below 1370 Iowa River Below Coralville Dam
Class A1 - Indicator Bacteria: 2010-2012 Site ID Data Source ID # Samples / # Years 2010 Geometric Mean 2011 Geometric Mean 2012 Geometric Mean Annual Geometric Mean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 10520003 6 24 / 3 117 132 75 Yes 4 17% No Evaluated Not Site ID Data Source ID # Samples / # Years Maximum Value Mean Value Median Value # Violations % Violations Significantly >10% Violations Assessment Type Support Level 10520003 6 33 / 3 8.4 8.02 8 0 0% No Evaluated Full 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 10520003 6 Ammonia 33 / 3 1.4 0.27 0.1 0 / 0 0% / 0% No Evaluated Full 10520003 6 Chloride 33 / 3 100 39 28 0 / 0 0% / 0% No Evaluated Full 10520003 6 Dissolved oxygen 33 / 3 16.5 10.2 10.1 NA / 0 NA / 0% No Evaluated Full 10520003 6 pH 33 / 3 8.4 8.02 8 0 / NA 0% / NA No Evaluated Full 10520003 6 Sulfate 33 / 3 66 39 35 0 / NA 0% / NA No Evaluated Full 10520003 6 Temperature 33 / 3 28.6 13.8 13.8 0 / 0 0% / 0% No Evaluated Full BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage BM Sample Gear BMIBI score BMIBI Class 72d BMIBI BIT BMIBI Pass/Fail 942 9/18/13 3323 72d MS Art Sub 15 Poor 51 Fail 942 9/14/12 3323 72d MS Art Sub 30 Poor 51 Fail Community Assessment Type Assessment Result Support Level IR Category Reason Benthic
Macroinvertebrates Evaluated Fail (0/2) WINOFI Assessment was evaluated because the
drainage area of Overall Evaluated Fail WINOFI 3bu the sample site 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) 1370 tissue plug 2021 channel catfish 5 45.3 0.107
1370 tissue plug 2021 smallmouth bass 9 26.4 0.124
Support Level Full
Class A1 - pH: 2012-2014
Class BWW1 - Binomial Parameters: 2012-2014
Class BWW1 - Biological Sampling:
Benthic Macroinvertebrates:
Overall:
Class HH - Fish Tissue Sampling: