Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Mississippi River IA 01-NEM-75

from Lock & Dam 11 at north side of Dubuque (Dubuque Co.) to Lock & Dam 10 at Guttenberg (Clayton Co.)

Cycle
2024
Release Status
Final
Overall IR
2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
Trend
Unknown
Created
11/1/2023 8:13:20 AM
Updated
2/2/2024 2:52:32 PM
Use Support
Class A1
Recreation - Primary contact
Fully Supported
Class BWW1
Aquatic Life - Warm Water Type 1
Fully Supported
Class HH
Human Health -
WINOFI
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Slight
Status
New
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2024
Impairment Rationale
Potential Impairment
Data Source
Fish contaminant monitoring: Iowa DNR
Impairment Delistings
Cycle Added Class Cause Data Source Rationale
2006 Class BWW1 Metals: Aluminum Ambient monitoring: adjacent state New data: WQ improvement (chemical / physical / bacterial)
Documentation
Assessment Summary

The Class A1 use was assessed as "fully supported" based on water quality monitoring data. The Class BWW1 use was assessed as “fully supported” based on water quality monitoring data. The Class HH use was assessed as "WINOFI" based fish tissue sampling data. According to DNR’s assessment methodology, the one-time occurrence of a level of mercury above an advisory trigger level does not suggest impairment of the fish consumption use. The Iowa DNR/DPH advisory protocol states that two consecutive samplings that show contaminant levels are above the trigger level in edible tissue are needed to justify issuance of an advisory.

Assessment Explanation

Data Sources:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

IEPA

10

WQ

CY 2020-2022

99990018

Mississippi River

Iowa DNR

6

FT

See Below

1142

Mississippi River

downstream of Guttenberg

Iowa DNR

6

FT

See Below

1159

Mississippi River

Mud Lake near Dubuque

Iowa DNR

6

FT

See Below

1381

Mississippi River

Guttenberg Boat Ramp


Class A1 - Indicator Bacteria: No Data


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

99990018

10

8 / 2

7.4

8.6

8

0

3

NO

Mon

Full


Class BWW1 - 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

99990018

10

Chloride

12 / 3

12.8

23

18.1

NA

0 / 0

4

NO

Mon

Full

99990018

10

Dissolved Oxygen

8 / 2

6.6

14.3

10.6

0

NA / NA

3

NO

Mon

Full

99990018

10

pH

8 / 2

7.4

8.6

8

0

NA / NA

3

NO

Mon

Full

99990018

10

Sulfate

12 / 3

11.4

37.2

22.8

0

NA / NA

4

NO

Mon

Full

99990018

10

Temperature

8 / 2

0

23.4

11

0

NA / NA

3

NO

Mon

Full


Class BWW1 - 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

99990018

10

Aluminum

12 / 3

959

349

272.5

0 / 1

NO

Mon

Full

99990018

10

Ammonia

7 / 2

0.36

0.12

0.09

0 / 0

NO

Eval

Full

99990018

10

Arsenic

12 / 3

18.5

2.3

1

0 / 0

NO

Mon

Full

99990018

10

Cadmium

12 / 3

184

16.7

1.5

1 / 1

NO

Mon

Full

99990018

10

Chromium

12 / 3

2.5

1.3

0.9

0 / 0

NO

Mon

Full

99990018

10

Copper

12 / 3

2.5

2.4

2.5

0 / 0

NO

Mon

Full

99990018

10

Cyanide

12 / 3

1

0.89

1

0 / 0

NO

Mon

Full

99990018

10

Lead

12 / 3

2.5

2.3

2.5

0 / 0

NO

Mon

Full

99990018

10

Nickel

12 / 3

2.5

1.6

1.1

0 / 0

NO

Mon

Full

99990018

10

Selenium

12 / 3

2.5

2.5

2.5

0 / 0

NO

Mon

Full

99990018

10

Silver

12 / 3

3.41

1.54

1.5

0 / 0

NO

Mon

Full

99990018

10

Zinc

12 / 3

5

3.5

2.5

0 / 0

NO

Mon

Full


Class HH-F - Toxic Parameters:

Site ID

Data Source ID

Parameter Name

# Samples per Year (2020/ 2021/2022)

2020 Mean

2021 Mean

2022 Mean

# Non-Detects per Year (2020/ 2021/2022)

Support Level per Year (2020/ 2021/2022)

Assessment Type

Support Level

99990018

10

Arsenic

4/4/4

1.075

1.02

1.09

0/0/2

Full/Full/Full

Mon

Full

99990018

10

Cadmium

4/4/4

0

0

0

4/4/4

Full/Full/Full

Mon

Full

99990018

10

Chromium

4/4/4

1.825

0.972

1.965

1/0/2

Full/Full/Full

Mon

Full

99990018

10

Chromium

4/4/4

1.825

0.972

1.965

1/0/2

Full/Full/Full

Mon

Full

99990018

10

Copper

4/4/4

2.185

0

0

3/4/4

Full/Full/Full

Mon

Full

99990018

10

Cyanide

4/4/4

0.67

0

0

2/4/4

Full/Full/Full

Mon

Full

99990018

10

Nickel

4/4/4

1.345

2.262

2.48

0/1/3

Full/Full/Full

Mon

Full

99990018

10

Selenium

4/4/4

0

0

0

4/4/4

Full/Full/Full

Mon

Full

99990018

10

Zinc

4/4/4

5.582

5.958

5.74

3/3/3

Full/Full/Full

Mon

Full


Class HH - Fish Tissue Sampling:

Site ID

Biopart

Year

Species

# in sample / # of samples

Avg Length (cm)

(Avg) Hg (ppm)

Chlordane (ppm)

Sum PCBs (ppm)

1159

tissue plug

2013

largemouth bass

5

35.0

0.165

1142

tissue plug

2015

largemouth bass

5

31.7

0.124

1142

fillet

2015

common carp

4

54.9

0.150

0.02

0.06

1381

tissue plug

2020

largemouth bass

20

32.7

0.244

1381

tissue plug

2020

northern pike

20

60.0

0.190

1381

tissue plug

2020

sauger

35

31.1

0.142

1381

tissue plug

2020

shovelnose sturgeon

10

49.3

0.056

1381

tissue plug

2020

walleye

15

43.6

0.207

1381

tissue plug

2020

yellow perch

20

22.3

0.082

1381

tissue plug

2021

freshwater drum

40

45.5

0.338

Support Level

WINOFI

3b



Monitoring and Methods
Assessment Key Dates
3/2/2020
Monitoring Start
12/14/2022
Monitoring End
9/18/2015
Fish Tissue Monitoring
7/1/2020
Fish Tissue Monitoring
10/3/2013
Fish Tissue Monitoring
8/6/2015
Fish Tissue Monitoring
7/1/2021
Fish Tissue Monitoring
Methods
200
Physical/Chemical Monitoring
260
Fish tissue analysis
860
Other Agencies/Organizations provided monitoring data