East Nishnabotna River IA 05-NSH-1415
from confluence with Fisher Cr. (S27 T69N R40W Fremont Co.) to Page/Montgomery county line
- Assessment Cycle
- 2022
- Release Status
- Final
- Data Collection Period
- Overall IR Category
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Stable
- Created
- 12/27/2021 2:47:20 PM
- Updated
- 1/13/2022 3:11:55 PM
Assessment Summary
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 BWW1 use was assessed as "WINOFI" based on biological sampling data. All other designated uses were "not assessed."
Assessment Explanation
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 WQ CY 2014-2016, CY 2018-2020 10360001 East Nishnabotna River near Shenandoah (US1)
Iowa DNR 6 BIO See Below 221 East
Nishnabotna River Shenandoah Site ID Data Source ID # Samples / # Years 2014 Geo. Mean 2015 Geo. Mean 2016 Geo. Mean Annual Geometric Mean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 10360001 6 24 / 3 991 772 561 Yes 17 71% Yes Evaluated 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 10360001 6 36 / 3 7.2 8.8 8 0 7 NO Monitored Full Class BWW1 -
Conventional Parameters: 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 10360001 6 Ammonia 36 / 3 0.02 0.61 0.05 NA 0 / 0 7 NO Monitored Full 10360001 6 Chloride 36 / 3 9.3 41 14.2 NA 0 / 0 7 NO Monitored Full 10360001 6 Dissolved Oxygen 36 / 3 7.5 14.5 10.6 0 NA / NA 7 NO Monitored Full 10360001 6 pH 36 / 3 7.2 8.8 8 0 NA / NA 7 NO Monitored Full 10360001 6 Sulfate 36 / 3 13 40 22 0 NA / NA 7 NO Monitored Full 10360001 6 Temperature 36 / 3 0 28.8 12.8 0 NA / NA 7 NO Monitored Full Class BWW1 -
Toxic Parameters: 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 10360001 6 Aluminum 14 / 3 13 4.19 2.35 0 / 0 NO Monitored Full 10360001 6 Arsenic 13 / 3 3.2 2 1.9 0 / 0 NO Monitored Full 10360001 6 Cadmium 13 / 3 0.26 0.05 0.02 0 / 0 NO Monitored Full 10360001 6 Chromium 13 / 3 1.7 0.7 0.6 0 / 0 NO Monitored Full 10360001 6 Lead 13 / 3 0.17 0.11 0.11 0 / 0 NO Monitored Full 10360001 6 Nickel 13 / 3 5 3 3 0 / 0 NO Monitored Full 10360001 6 Silver 13 / 3 0.025 0.025 0.025 0 / 0 NO Monitored Full 10360001 6 Zinc 13 / 3 4.6 2.2 2.5 0 / 0 NO Monitored Full Site ID Date Drainage Area (mi2) Ecoregion Major Drainage BM Sample Gear BMIBI score BMIBI Class 47e BMIBI BIT BMIBI Pass/Fail 221 8/12/20 1022 47e MO Floating Art Sub 24 Poor 54 Fail 221 9/6/16 1022 47e MO Floating Art Sub 44 Fair 54 Fail Overall: Community Assessment Type Assessment Result Support Level IR Category Reason Benthic
Macroinvertebrates Evaluated Fail (0/2) Not Assessment was evaluated
because the drainage area of the sample site Overall Evaluated Fail WINOFI 3bu was greater than the
calibrated range.
Class A1 - Indicator Bacteria:
Class A – pH:
Class BWW1 - Biological Sampling:
Benthic Macroinvertebrates:
Class HH - No Data
Assessment Key Dates
| 8/12/2020 | Biological Monitoring |
| 9/6/2016 | Biological Monitoring |
| 1/7/2014 | Fixed Monitoring Start Date |
| 12/6/2016 | Fixed Monitoring End Date |
| 1/8/2018 | Fixed Monitoring Start Date |
| 12/1/2020 | Fixed Monitoring End Date |
Methods
| 150 | Monitoring data more than 5 years old |
| 230 | Fixed station physical/chemical (conventional plus toxic pollutants) |
| 315 | Regional reference site approach |
| 320 | Benthic macroinvertebrate surveys |
| 420 | Indicator bacteria monitoring |