Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Cloie Branch IA 01-TRK-134

mouth (S5 T89N R2E Dubuque Co.) to west line of S5 T89N R2E Dubuque Co.

This is a DRAFT assessment
Draft assessments may change without notice
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 3:09:02 PM
Updated
1/9/2026 11:07:54 AM
Use Support
Class A1
Recreation - Primary contact
Fully Supported
Class A2
Recreation - Secondary contact
Fully Supported
Class BCW1
Aquatic Life - Cold Water Type 1
Not Supported
Support Level
Not Supported
Impairment Code
5b-v - Biological - verified
Cause Magnitude
Moderate
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2016
Impairment Rationale
Low Biotic Index
Data Source
Biological monitoring: Iowa DNR WQMA
TMDL Priority
Tier IV
Support Level
Not Supported
Impairment Code
5a - Pollutant-caused impairment. TMDL needed.
Cause Magnitude
High
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2016
Impairment Rationale
Significantly > 10% of samples fail to meet criterion
Data Source
Biological monitoring: Iowa DNR WQMA
TMDL Priority
Tier IV
Class HH
Human Health -
Not Assessed
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The presumptive Class A1 and Class A2 uses were assessed as "fully supported" based on pH monitoring data. The Class BCW1 use was assessed as "not supported" based on biological sampling data, grab sample temperature data, and continuous temperature monitoring data. All other designated uses were "not assessed." DNR is unsure that this segment should be designated as a coldwater stream. If this segment was assessed as a warm water stream segment, there would be no violations of the temperature water quality criteria. Additionally, the biological assessment of warm water aquatic life use would also indicate "full support."

Assessment Explanation

DNR is unsure that this segment should be designated as a coldwater stream. If this segment was assessed as a warm water stream segment, there would be no violations of the temperature water quality criteria. Additionally, the biological assessment of the warm water aquatic life use would also indicate "full support."

Data Sources:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

Iowa DNR

6

WQ

CY 2022

12310006

Cloie Branch-Durango

Iowa DNR

6

BIO & WQ

See Below

836

Cloie Branch

Durango (REMAP #389)

Presumptive Class A1 - Indicator Bacteria: No Data

Presumptive Class A1 & A2 – 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

12310006

6

7 / 1

7.32

8.37

7.91

0

3

NO

EVALUATED

FULL

Class BCW1 - Binomial 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

12310006

6

Dissolved Oxygen

7 / 1

8.44

12.37

10.63

0

NA / NA

3

NO

EVALUATED

FULL

12310006

6

pH

7 / 1

7.32

8.37

7.91

0

NA / NA

3

NO

EVALUATED

FULL

12310006

6

Temperature

7 / 1

7.193

25.206

17.504

4

NA / NA

3

YES

MONITORED

NOT


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

836

7/13/21

5.6

52b

MS/CW

Hess

24

NA

60

Fail


Overall Assessment:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Fail (0/1)

Not

5bv

Assessment was evaluated because it was based on a single sample.



(Theoretical Assessment) Class BWW1 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/Thermal

BM Sample Gear

BMIBI score

BMIBI Class

52b BMIBI BIT

BMIBI Pass/Fail

836

7/13/21

5.6

52b

MS/CW

Hess

68

Good

61

Pass


Fish:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/ Thermal

Riffle Stream?

FIBI score

FIBI Class

52b FIBI BIT

FIBI Pass/Fail

836

7/13/21

5.6

52b

MS/CW

NA

73

Excellent

52

Pass


Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Pass (1/1)

Full

Fish

Evaluated

Pass (1/1)

Full

1

Overall

Evaluated

Pass

Full

Assessment was evaluated because it was based on a single sample.


Class BCW1 - Continuous Monitoring Data:

Continuous monitoring data collected in 2013 and 2014 at Site 836 were examined for stream temperature criteria violations. The maximum stream temperature recorded during the sensor deployment period was 30.9 degrees (C). The BCW1 temperature criterion of 20 (C) was exceeded in 121 of 126 days. The percentage exceeding (96%) was greater than the 10% impairment threshold with high statistical confidence (>90%). Based on these data, the BCW1 use was assessed as impaired due to temperature.

Class HH - No Data

Monitoring and Methods
Assessment Key Dates
7/3/2021
Biological Monitoring
7/18/2013
Monitoring Start
9/15/2014
Monitoring End
4/20/2022
Monitoring Start
10/18/2022
Monitoring End
Methods
150
Monitoring data more than 5 years old
200
Physical/Chemical Monitoring
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys