Ten Mile Creek IA 01-UIA-274
mouth (S1 T98N R9W Winneshiek Co.) to confluence with Walnut Cr. in S18 T98N R9W Winneshiek Co.
- Assessment Cycle
- 2022
- Release Status
- Final
- Data Collection Period
- Overall IR Category
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 12/14/2021 2:52:44 PM
- Updated
- 1/6/2022 9:20:08 AM
The presumptive Class A1 use was assessed as “not supported” based on levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class A2 use was assessed as “fully supported” based on indicator bacteria (E. coli) monitoring data. The Class BCW1 use was assessed as "not supported" based on biological sampling data. All other designated uses were “not assessed.”
Data Sources:
Data Source |
Data Source ID |
Data Type |
Data Age |
Site ID |
Site Name |
Site Description |
Iowa DNR |
6 |
BIO |
See Below |
476 |
Ten Mile Creek |
Decorah – REMAP #169 |
Iowa DNR |
6 |
BIO |
See Below |
829 |
Ten Mile Creek |
Ridgeway |
NEIARCD |
19 |
WQ |
CY2012-2014 |
191910006 |
Ten Mile Creek |
Site 26 |
Presumptive Class A1 - Indicator Bacteria:
Site ID |
Data Source ID |
# Samples / # Years |
2012 Geometric Mean |
2013 Geometric Mean |
2014 Geometric Mean |
Annual Geometric Mean Violation |
# Violations |
% Violations |
Significantly >10% Violations |
Assessment Type |
Support Level |
191910006 |
19 |
21 / 3 |
110 |
315 |
506 |
Yes |
12 |
57% |
Yes |
Evaluated |
Not |
Class A2 - Indicator Bacteria:
Site ID |
Data Source ID |
# Samples / # Years |
2012 Geometric Mean |
2013 Geometric Mean |
2014 Geometric Mean |
Annual Geometric Mean Violation |
# Violations |
% Violations |
Significantly >10% Violations |
Assessment Type |
Support Level |
191910006 |
19 |
21 / 3 |
110 |
315 |
506 |
No |
3 |
14% |
No |
Evaluated |
Full |
Class A - pH:
Site ID |
Data Source ID |
# Samples / # Years |
Maximum Value |
Mean Value |
Median Value |
# Violations |
% Violations |
Significantly >10% Violations |
Assessment Type |
Support Level |
191910006 |
19 |
13 / 3 |
10.93 |
8.65 |
8.37 |
2 |
15% |
No |
Evaluated |
Full |
Class BCW1 - 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 |
191910006 |
19 |
Ammonia |
14 / 3 |
0.18 |
0.06 |
0.05 |
0 / 0 |
0% / 0% |
No |
Evaluated |
Full |
191910006 |
19 |
pH |
13 / 3 |
10.93 |
8.65 |
8.37 |
2 / 0 |
15% / 0% |
No |
Evaluated |
Full |
191910006 |
19 |
Temperature |
14 / 3 |
21.1 |
14.7 |
16.4 |
NA / 0 |
NA / 0% |
No |
Evaluated |
Full |
Class BCW1 - Biological Sampling:
Benthic Macroinvertebrates:
BioNet Site ID |
Date |
Drainage Area (mi2) |
Ecoregion |
Major Drainage/ Thermal |
BM Sample Gear |
CBI score |
CBI Class |
CBI BIT |
CBI Pass/ Fail |
476 |
8/12/14 |
29 |
52b |
MS/CW |
Hess |
56 |
NA |
60 |
Fail |
476 |
8/7/13 |
13 |
52b |
MS/CW |
Hess |
66 |
NA |
60 |
Pass |
829 |
8/16/11 |
29 |
52b |
MS/CW |
Hess |
50 |
NA |
60 |
Fail |
Overall Assessment:
Community |
Assessment Type |
Assessment Result |
Support Level |
IR Category |
Reason |
Benthic Macroinvertebrates |
Evaluated |
Fail (1/3) |
Not |
5bv |
Assessment was evaluated because samples used to complete assessment weren’t collected in the last five years. |
Class BCW1-Natural Trout Reproduction:
In contrast to the Benthic Macroinvertebrate data, based on the January 2021 summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau, the Class BCW1 coldwater aquatic life use of Ten Mile Creek was assessed as "fully supported.” According to the updated summary, this stream was placed in Category II: streams that exhibit recent but inconsistent reproductive success and occasional stocking may be needed to maintain the trout population.
Class HH - No Data