Missouri River IA 06-WEM-1709
from water supply intake at Council Bluffs (River Mile 619 in SE 1/4 S22 T75N R44W Pottawattamie Co.) to confluence with Boyer R. in Pottawattamie 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 3:10:45 PM
- Updated
- 1/15/2026 10:30:24 AM
The Class A1 use remains assessed as “not supported” due to levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class BWW1 use remains assessed as "not supported" based on historic information from local fisheries biologists on impacts related to navigation-related flow modifications and habitat alterations in this segment of the Missouri River. The Class C use remains assessed as “fully supported” based on water quality monitoring data and drinking water compliance monitoring reporting required by the DNR. All other designated uses were "not assessed."
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site
Name Site
Description USACE 12 WQ CY 2022-2024 99990119 Missouri
River
IA PWS 27 WQ CY 2022-2024 99990202 Missouri
River
Site ID Data Source ID # Samples per Year (2022/ 2023/2024) 2022 Geometric Mean 2023 Geometric Mean 2024 Geometric Mean Violates Annual Geometric Mean? # 2022 SSM violations / SSM Violations needed for impairment # 2023 SSM violations / SSM Violations needed for impairment # 2024 SSM violations / SSM Violations needed for impairment Violates Annual SSM Significantly >10% Rule? Assessment Type Support Level 99990119 12 7/9/8 178 139 123 YES 3 / 3 4 / 3 3 / 3 YES MONITORED 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 99990119 12 34 / 3 7.23 8.42 8.07 0 7 NO MONITORED 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 99990119 12 Chloride 30 / 3 14 20 17 NA 0 / 0 6 NO MONITORED FULL 99990119 12 Dissolved Oxygen 35 / 3 6.22 13.66 10.1 0 NA / NA 7 NO MONITORED FULL 99990119 12 pH 34 / 3 7.23 8.42 8.07 0 NA / NA 7 NO MONITORED FULL 99990119 12 Sulfate 30 / 3 180 281 225 0 NA / NA 6 NO MONITORED FULL 99990119 12 Temperature 35 / 3 -0.03 28.09 13.4 0 NA / NA 7 NO MONITORED 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 99990119 12 Ammonia 30 / 3 0.499 0.1 0.06 0 / 0 NO MONITORED FULL The Class BWW1 use remains assessed as "not
supported" (IR Category 4c, non-pollutant stressor) based on the
assessment developed for the 1998, 2000, and 2002 reports (i.e., habitat
alterations and flow modifications that resulted from development of the river
for navigation uses in the mid-Twentieth Century). The assessment was developed
in consultation with the Nebraska Missouri River fisheries biologist. Site ID Data Source ID Parameter Name # Samples / # Years Minimum Value Maximum Value Mean Value Median Value # Violations Violates Significantly >10% Rule? Assessment Type Support Level 99990119 12 Chloride 32 / 3 14 20 17 17 0 NO MONITORED FULL 99990119 12 Inorganic nitrogen (nitrate and nitrite) 32 / 3 0.0125 5.3 1.1 0.8 0 NO MONITORED FULL 99990202 27 Nitrate 1091 / 3 0.1 4.6 1 0.8 0 NO MONITORED FULL 99990119 12 pH 34 / 3 7.23 8.42 8.07 8.13 0 NO MONITORED FULL 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 99990119 12 Atrazine 19 / 2 0.9 0.2 0.05 12 NO MONITORED FULL
Compliance monitoring required by the Iowa DNR Water Supply
Operations and Engineering Sections did not show violations of finished water
caused by source water at the Council Bluffs Water Works facility during the
2022-24 monitoring period. The results of compliance monitoring as reported in
annual compliance reports are available at the following location at the Iowa
DNR’s home page: https://www.iowadnr.gov/Environmental-Protection/Water-Quality/Water-Supply-Engineering/Annual-Compliance-Report.
Class A1 - Indicator Bacteria:
Class A1 – pH:
Class BWW1 - Binomial Parameters:
Class BWW1 - Toxic Parameters:
Class BWW1 – Historical Assessment:
Class C - Binomial Parameters:
Class C - Toxic Parameters:
Class C - Iowa Drinking Water Compliance Report:
Class HH - No Data