Old Mans Creek IA 02-IOW-686
from confluence with unnamed tributary (N line S1 T78N R7W Johnson Co.) to confluence with unnamed tributary in NE 1/4 S4 T78N R8W Johnson Co.
- Assessment Cycle
- 2022
- Release Status
- Final
- Data Collection Period
- Overall IR Category
- 4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
- Trend
- Unknown
- Created
- 12/27/2021 6:03:29 AM
- Updated
- 12/27/2021 6:08:55 AM
| Cycle Added | Class | Cause | Data Source | Rationale |
|---|---|---|---|---|
| 2006 | Class BWW2 | Biological: low fish IBI | Biological monitoring: Iowa DNR WQMA | New data: recovery of fish/invertebrate community |
Assessment Summary
The presumptive Class A1 use remains assessed as "not supported" due to levels of indicator bacteria 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. 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 5p (impaired; TMDL needed) to 4a (impaired; TMDL approved).
Assessment Explanation
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 WQ CY 2018-2020 10520001 Old Mans Creek nr Iowa City
Iowa DNR 6 BIO See Below 1047 Old
Mans Creek Sharon
Center Iowa DNR 6 BIO See Below 5 Old
Mans Creek Williamstown Presumptive Class
A1 - Indicator Bacteria: Site ID Data Source ID # Samples per Year (2018/ 2019/2020) 2018 Geometric Mean 2019 Geometric Mean 2020 Geometric Mean Violates Annual Geometric Mean? # 2018 SSM violations / SSM Violations
needed for impairment # 2019 SSM violations / SSM Violations
needed for impairment # 2020 SSM violations / SSM Violations
needed for impairment Violates Annual SSM Significantly >10%
Rule? Assessment Type Support Level 10520001 6 4/5/8 200 1222 779 YES 2 / NA 3 / NA 7 / 3 YES Monitored Not Class A - pH 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 10520001 6 36 / 3 6.6 8.4 7.9 0 7 NO Monitored Full Class BWW2 -
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 10520001 6 Ammonia 36 / 3 0.025 0.8 0.1 NA 0 / 0 7 NO Monitored Full 10520001 6 Chloride 36 / 3 17 57 28 NA 0 / 0 7 NO Monitored Full 10520001 6 Dissolved Oxygen 36 / 3 4.1 14 10.1 2 NA / NA 7 NO Monitored Full 10520001 6 pH 36 / 3 6.6 8.4 7.9 0 NA / NA 7 NO Monitored Full 10520001 6 Sulfate 36 / 3 8 55 24 0 NA / NA 7 NO Monitored Full 10520001 6 Temperature 36 / 3 0 26.6 11.5 0 NA / NA 7 NO Monitored Full Class BWW2 -
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 10520001 6 Aluminum 14 / 3 8.3 1.7 0.5 0 / 0 NO Monitored Full 10520001 6 Arsenic 13 / 3 1.9 1.1 1.1 0 / 0 NO Monitored Full 10520001 6 Cadmium 13 / 3 0.05 0.03 0.02 0 / 0 NO Monitored Full 10520001 6 Chromium 13 / 3 1 0.7 0.8 0 / 0 NO Monitored Full 10520001 6 Lead 13 / 3 0.26 0.14 0.11 0 / 0 NO Monitored Full 10520001 6 Nickel 13 / 3 5.4 3.3 3.2 0 / 0 NO Monitored Full 10520001 6 Silver 13 / 3 0.025 0.025 0.025 0 / 0 NO Monitored Full 10520001 6 Zinc 13 / 3 5.1 2.5 2.4 0 / 0 NO Monitored Full Site ID Date Drainage Area (mi2) Ecoregion Major Drainage BM Sample Gear BMIBI score BMIBI Class 47f BMIBI BIT BMIBI Pass/ Fail 1047 8/7/20 210 47f MS Floating Art Sub 63 Good 51 Pass 5 9/18/19 138 47f MS Art Sub 52 Fair 51 Pass 1047 9/19/16 210 47f MS Floating Art Sub 64 Good 51 Pass Fish: Site ID Date Drainage Area (mi2) Ecoregion Major Drainage Riffle Stream? FIBI score FIBI Class 47f FIBI BIT FIBI Pass/ Fail 5 9/18/19 138 47f MS NA 53 Good 36 Pass 1047 9/22/16 210 47f MS NA 34 Fair 36 Fail 5 10/7/15 138 47f MS NA 38 Fair 36 Pass Overall: Community Assessment Type Assessment Result Support Level IR Category Reason Benthic
Macroinvertebrates Monitored Pass (3/3) Full
Fish Monitored Pass (2/3) Full 1 Assessment was monitored
because the samples used to complete Overall Monitored Pass Full the assessment were
collected in a recent five year period.
Class BWW2 - Biological Sampling:
Benthic Macroinvertebrates:
Assessment Key Dates
| 9/18/2019 | Biological Monitoring |
| 8/7/2020 | Biological Monitoring |
| 1/4/2018 | Fixed Monitoring Start Date |
| 12/8/2020 | Fixed Monitoring End Date |
| 10/7/2015 | Biological Monitoring |
| 9/19/2016 | Biological Monitoring |
| 9/22/2016 | Biological Monitoring |
| 3/9/2018 | TMDL Completed |
Methods
| 230 | Fixed station physical/chemical (conventional plus toxic pollutants) |
| 315 | Regional reference site approach |
| 320 | Benthic macroinvertebrate surveys |
| 330 | Fish surveys |
| 420 | Indicator bacteria monitoring |