Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Badger Lake IA 04-UDM-1291

Webster County S19T90NR28W 4.5 mi N of Fort Dodge.

This is a DRAFT assessment
Draft assessments may change without notice
Cycle
2026
Current Phase
Public Comment
Overall IR
2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
Trophic
Eutrophic
Trend
Stable
Created
10/27/2025 3:10:06 PM
Updated
11/20/2025 10:44:24 AM
Use Support
Class A1
Recreation - Primary contact
Fully Supported
Class BLW
Aquatic Life - Lakes and wetlands
WINOFI
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Moderate
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2002
Impairment Rationale
Adverse impacts on plant/animal communities
Data Source
Biological monitoring: Iowa DNR Fisheries
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Moderate
Status
Continuing
Source
Agriculture
Source Confidence
Moderate
Cycle Added
2002
Impairment Rationale
Adverse impacts on plant/animal communities
Data Source
Biological monitoring: Iowa DNR Fisheries
Class HH
Human Health -
Not Assessed
Impairment Delistings
Cycle Added Class Cause Data Source Rationale
2020 Class A1 Turbidity: Secchi Disk Transparency Ambient monitoring: Iowa DNR-lakes New data: WQ improvement (chemical / physical / bacterial)
Documentation
Assessment Summary

The Class A1 use remains assessed (monitored) as "fully supported." The Class BLW use was assessed (evaluated) as “WINOFI” due to water quality impacts of common carp. All other designated uses were “not assessed.”

Assessment Explanation

Data Sources:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

Iowa DNR

6

WQ

CY 2020-2024

22940001

Badger Lake

Class A - 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

22940001

6

14 / 5

7.55

9.06

8.3

1

4

NO

MONITORED

FULL

Class A1 - Lake TSI's

Site ID

Data Source ID

Parameter Name

# Samples / # Years

Minimum Value

Maximum Value

Median Value

Median TSI Violation?

Assessment Type

Support Level

22940001

6

Chlorophyll a TSI

14 / 5

35

83

64

NO

MONITORED

FULL

22940001

6

Secchi TSI

14 / 5

45

70

61

NO

MONITORED

FULL

22940001

6

Total Phosphorus TSI

14 / 5

35

83

65

NA

NA

NA

22940001

6

Fixed suspended solids

14 / 5

1.6

16

3

NA

NA

NA

DNR's assessment methodology indicates that a TSI value less than or equal to 63 are necessary to suggest de-listing of an impairment. The Secchi depth TSI value for the 2020 assessment listing cycle was 65, which based on DNR's assessment/listing methodology indicated an impairment based on the narrative criteria protecting against aesthetically objectionable conditions. Because the TSI value for the 2026 assessment/listing cycle is less than or equal to the delisting trigger of 63 (median TSI value for Secchi depth was 61), based on DNR's methodology, these values suggest "full support" of the Class A1 uses protecting against aesthetically objectionable conditions and the impairment (5a) for Secchi depth is suggested for delisting for the 2026 assessment/listing cycle.

Class BLW - 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

22940001

6

Dissolved Oxygen

13 / 5

7.4

16.4

11.4

0

NA / NA

4

NO

MONITORED

FULL

22940001

6

pH

14 / 5

7.55

9.06

8.3

1

NA / NA

4

NO

MONITORED

FULL

22940001

6

Temperature

14 / 5

15.5

28.7

23

0

NA / NA

4

NO

MONITORED

FULL

Class BLW - Lake Planktonic Cyanobacteria:

Site ID

Data Source ID

# Samples

Maximum Cyanobacteria Wet Mass

Maximum Cyanobacteria % Composition

Median Cyanobacteria Wet Mass

Median Cyanobacteria % Composition

Median Cyanobacteria Concentration = 75th Percentile

Assessment Type

Support Level

22940001

6

5

1.464794449

19.25%

0.00727672

0.04%

NO

EVALUATED

NA

Class BLW - 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

22940001

6

Ammonia

14 / 5

0.222

0.06

0.03

0 / 0

NO

MONITORED

FULL


Class HH - No Data

Additional information: The Class BLW use was assessed (evaluated) as “WINOFI” based on information from the DNR Fisheries Bureau. Information from the DNR Fisheries Bureau suggests that siltation and the impacts of common carp on turbidity at this lake impair the aquatic life use.

Monitoring and Methods
Assessment Key Dates
5/19/2020
Monitoring Start
9/19/2024
Monitoring End
Methods
200
Physical/Chemical Monitoring
340
Primary producer surveys (phytoplankton/periphyton/macrophyton)