Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Muddy Creek IA 02-IOW-2043

from mouth (S33 T80N R6W Johnson Co.) to headwaters in SW 1/4 S12 T80N R7W Johnson Co.

Cycle
2022
Release Status
Final
Overall IR
4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
Trend
Unknown
Created
12/28/2021 8:21:01 AM
Updated
1/14/2022 3:12:54 PM
Use Support
Class A1
Recreation - Primary contact
Not Supported
Support Level
Not Supported
Impairment Code
4a - Pollutant-caused impairment. TMDL has been completed.
Cause Magnitude
High
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2008
Impairment Rationale
Geometric mean criterion exceeded
Data Source
Special project/study
Class BWW1
Aquatic Life - Warm Water Type 1
WINOFI
Impairment Code
3b-u - Use potentially biologically impaired based on uncalibrated IBI metrics.
Cause Magnitude
Slight
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2008
Impairment Rationale
Low Biotic Index
Data Source
Biological monitoring: Iowa DNR WQMA
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The Class A1 use was assessed as “not supported” due to levels of indicator bacteria (E. coli) that exceeded Iowa’s water quality criteria. The presumptive Class BWW1 use was assessed as “WINOFI” 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).

Assessment Explanation

Data Sources:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

USGS

11

WQ

CY 2018-2019

5454050

Muddy Cr abv Trtmnt Outfall at North Liberty, IA

USGS

11

WQ

CY 2018-2019

5454052

Muddy Cr blw Trtmnt Outfall at North Liberty, IA

USGS

11

WQ

CY 2018-2019

5454090

Muddy Creek at Coralville, IA

Iowa DNR

6

WQ

CY 2012-2013

15520002

Muddy Creek at Golf View Dr (MCB)

Iowa DNR

6

WQ

CY 2012-2013

15520003

Muddy Creek at 1 Ave (MC3)

Iowa DNR

6

WQ

CY 2012-2013

16520003

Muddy Creek (MCR1)

Iowa DNR

6

WQ

CY 2012-2013

16520004

Muddy Creek (MCR2)

Iowa DNR

6

BIO

See Below

630

Muddy Creek

North Liberty – DS WWTP


Presumptive Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples / # Years

2012 Geometric Mean

2013 Geometric Mean

Annual Geometric Mean Violation

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

15520002

6

21 / 2

1126

1520

Yes

19

90%

Yes

Evaluated

Not

15520003

6

21 / 2

897

848

Yes

21

100%

Yes

Evaluated

Not

16520003

6

21 / 2

724

1205

Yes

19

90%

Yes

Evaluated

Not

16520004

6

21 / 2

949

707

Yes

19

90%

Yes

Evaluated

Not


Presumptive Class A1 – 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

5454050

11

9 / 2

7

7.7

7.5

0

3

NO

Evaluated

Full

5454052

11

9 / 2

7.2

7.8

7.6

0

3

NO

Evaluated

Full

5454090

11

9 / 2

7.6

8.2

7.9

0

3

NO

Evaluated

Full


Presumptive 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

5454050

11

Dissolved Oxygen

9 / 2

7

13.5

9.2

0

NA / NA

3

NO

Evaluated

Full

5454052

11

Dissolved Oxygen

9 / 2

7.7

11.7

9.4

0

NA / NA

3

NO

Evaluated

Full

5454090

11

Dissolved Oxygen

9 / 2

7.9

14.4

10.6

0

NA / NA

3

NO

Evaluated

Full

5454050

11

pH

9 / 2

7

7.7

7.5

0

NA / NA

3

NO

Evaluated

Full

5454052

11

pH

9 / 2

7.2

7.8

7.6

0

NA / NA

3

NO

Evaluated

Full

5454090

11

pH

9 / 2

7.6

8.2

7.9

0

NA / NA

3

NO

Evaluated

Full

5454050

11

Temperature

9 / 2

0.4

21.4

11

0

NA / NA

3

NO

Evaluated

Full

5454052

11

Temperature

9 / 2

7.1

20.6

15

0

NA / NA

3

NO

Evaluated

Full

5454090

11

Temperature

9 / 2

0

22

11

0

NA / NA

3

NO

Evaluated

Full


Presumptive Class BWW1 - Biological Sampling:


Benthic Macroinvertebrates:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

BM Sample Gear

BMIBI score

BMIBI Class

47f BMIBI BIT

BMIBI Pass/Fail

630

10/12/09

4

47f

MS

Art Sub

54

Fair

51

Pass

Fish:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

Riffle Stream?

FIBI score

FIBI Class

47f FIBI BIT

FIBI Pass/Fail

630

9/29/10

4

47f

MS

NA

30

Fair

36

Fail

630

10/12/09

4

47f

MS

NA

13

Poor

36

Fail

Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Pass (1/1)

Full

Fish

Evaluated

Fail (0/2)

Not

Assessment was evaluated because the drainage area of the site used

Overall

Evaluated

Fail

WINOFI

3bu

for the assessment was smaller than the calibrated range.


Monitoring and Methods
Assessment Key Dates
10/12/2009
Biological Monitoring
9/29/2010
Biological Monitoring
5/1/2012
Non-fixed Monitoring Start Date
8/30/2013
Non-fixed Monitoring End Date
1/8/2018
Non-fixed Monitoring Start Date
7/16/2019
Non-fixed Monitoring End Date
3/9/2018
TMDL Completed
Methods
150
Monitoring data more than 5 years old
220
Non-fixed station physical/chemical monitoring (conventional pollutant only)
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys
380
Quantitative physical habitat assessment
420
Indicator bacteria monitoring