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
- 2020
- Release Status
- Final
- Data Collection Period
- Overall IR Category
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 9/3/2020 12:58:44 PM
- Updated
- 10/12/2020 1:08:01 PM
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 remains assessed as "partially supported” based on biological 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 5p (impaired; TMDL needed) to 4a (impaired; TMDL approved). Because not all impairments identified for this segment are covered by the TMDL, this segment remains in Category 5 of Iowa's Integrated Report (impaired; TMDL needed).
Assessment Explanation
Sources of
Data: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 WQ CY 2016-2018 10520001 Old Mans Creek nr Iowa City Iowa DNR 6 BIO See Below 5 Old Mans Creek Williamstown Iowa DNR 6 BIO See Below 1047 Old Mans Creek Sharon Center Presumptive Class A1 -
Indicator Bacteria: Site ID Data Source ID # Samples / # Years 2016 Geometric Mean 2017 Geometric Mean 2018 Geometric Mean Annual Geometric Mean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 10520001 6 16 / 3 1636.65 1070.75 199.57 Yes 13 81% Yes Monitored Not Presumptive Class A1 - pH: Site ID Data Source ID # Samples / # Years Maximum Value Mean Value Median Value # Violations % Violations Significantly >10% Violations Assessment Type Support Level 10520001 6 36 / 3 8.3 7.9 8 0 0% No Monitored Full Class BWW2 -
Conventional Parameters: 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 10520001 6 Ammonia 36 / 3 0.8 0.09 0.02 0 / 0 0% / 0% No Monitored Full 10520001 6 Chloride 36 / 3 57 27 24 0 / 0 0% / 0% No Monitored Full 10520001 6 Dissolved oxygen 36 / 3 13.8 9.7 9.1 NA / 2 NA / 6% No Monitored Full 10520001 6 pH 36 / 3 8.3 7.9 8 0 / NA 0% / NA No Monitored Full 10520001 6 Sulfate 36 / 3 55 24.4 21 0 / NA 0% / NA No Monitored Full 10520001 6 Temperature 36 / 3 26.8 11.3 10.6 0 / 0 0% / 0% No Monitored Full Class
BWW2 - Biological Sampling: Benthic
Macroinvertebrates: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/Thermal BM Sample Gear BMIBI score BMIBI Class 47f BMIBI BIT BMIBI Pass/ Fail 1047 9/19/16 210 47f MS/WW Float ArtSub 64 Good 51 Pass 5 10/7/15 138 47f MS/WW ArtSub 48 Fair 51 Fail 1047 9/8/15 210 47f MS/WW Float ArtSub 69 Good 51 Pass Fish: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/Thermal Riffle Stream? FIBI score FIBI Class 47f FIBI BIT FIBI Pass/ Fail 1047 9/22/16 210 47f MS/WW NA 34 Fair 36 Fail 5 10/7/15 138 47f MS/WW NA 38 Fair 36 Pass 5 10/11/10 138 47f MS/WW NA 24 Poor 36 Fail
Overall: Community Assessment Type Assessment Result Support Level Earned IR Category Actual IR Category Reason Benthic
Macroinvertebrates Monitored Pass (2/3) Full Fish Evaluated Fail (1/3) Partial Overall Evaluated Fail Partial 3bc 5bt Assessment
is evaluated because it included samples not collected in the last five years. Class BWW2 -
Toxic Parameters: Site ID Data Source ID Parameter Name # Samples / # Years Maximum Value Mean Value Median Value # Acute / Chronic Violations % Acute/ Chronic Violations >1 Acute / Chronic Violation Assessment Type Support Level 10520001 6 Aluminum 9 / 2 8.3 1.867 0.32 0 / 0 0% / 0% No Evaluated Full 10520001 6 Arsenic 9 / 2 1.9 1.33 1.4 0 / 0 0% / 0% No Evaluated Full 10520001 6 Cadmium 9 / 2 0.05 0.028 0.025 0 / 0 0% / 0% No Evaluated Full 10520001 6 Chromium 9 / 2 0.99 0.72 0.79 0 / 0 0% / 0% No Evaluated Full 10520001 6 Copper 9 / 2 2.8 1.135 0.99 0 / 0 0% / 0% No Evaluated Full 10520001 6 Lead 9 / 2 0.26 0.089 0.11 0 / 0 0% / 0% No Evaluated Full 10520001 6 Nickel 9 / 2 5.4 3.4 3.6 0 / 0 0% / 0% No Evaluated Full 10520001 6 Selenium 9 / 2 1.4 0.87 1 0 / 0 0% / 0% No Evaluated Full 10520001 6 Zinc 9 / 2 4.8 1.98 2.2 0 / 0 0% / 0% No Evaluated Full
Assessment Key Dates
9/8/2015 | Biological Monitoring |
10/11/2010 | Biological Monitoring |
1/6/2016 | Fixed Monitoring Start Date |
12/10/2018 | 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
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 |
330 | Fish surveys |
420 | Indicator bacteria monitoring |