Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Fourmile Creek IA 04-LDM-1112

mouth (S16 T78N R23W Polk Co.) to county road bridge (First Street Ankeny) in S18 T80N R23W PolkCo.

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.
Trend
Stable
Created
10/27/2025 3:09:04 PM
Updated
1/13/2026 11:13:57 AM
Use Support
Class A1
Recreation - Primary contact
Not Assessed
Class BWW2
Aquatic Life - Warm Water Type 2
Fully Supported
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The Class BWW2 use was assessed as "fully supported" based on biological sampling data and water quality monitoring data. 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

BIO

See Below

1242

Fourmile Creek

Berwick

PCCB

29

WQ

CY 2022-2024

99990217

Four Mile Creek

PCCB

29

WQ

CY 2022-2024

99990224

Four Mile Creek

PCCB

29

WQ

CY 2022-2024

99990292

Four Mile Creek

PCCB

29

WQ

CY 2022-2024

99990234

Four Mile Creek

PCCB

29

WQ

CY 2022-2024

99990241

Four Mile Creek

PCCB

29

WQ

CY 2022-2024

99990242

Four Mile Creek

PCCB

29

WQ

CY 2022-2024

99990257

Four Mile Creek


Class A1 - No Data


Class BWW2 - 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

99990217

29

Chloride

6 / 2

11.39

74.92

48.77

NA

0 / 0

3

NO

EVALUATED

FULL

99990224

29

Chloride

5 / 3

44.19

83.48

59.7

NA

0 / 0

2

NO

EVALUATED

FULL

99990292

29

Chloride

6 / 3

15

70.8

44

NA

0 / 0

3

NO

EVALUATED

FULL

99990217

29

Sulfate

6 / 2

11.07

47.43

31.09

0

NA / NA

3

NO

EVALUATED

FULL

99990224

29

Sulfate

5 / 3

27.89

51.77

37.46

0

NA / NA

2

NO

EVALUATED

FULL

99990292

29

Sulfate

6 / 3

11.72

50.94

30.56

0

NA / NA

3

NO

EVALUATED

FULL

99990217

29

Temperature

52 / 3

0

31.11

14.44

0

NA / NA

9

NO

MONITORED

FULL

99990224

29

Temperature

62 / 3

0

31.67

15.57

0

NA / NA

10

NO

MONITORED

FULL

99990234

29

Temperature

48 / 3

-1.11

29.44

14.01

0

NA / NA

9

NO

MONITORED

FULL

99990241

29

Temperature

41 / 3

-1.11

26.67

13.33

0

NA / NA

8

NO

MONITORED

FULL

99990242

29

Temperature

46 / 3

-1.11

27.78

13.35

0

NA / NA

8

NO

MONITORED

FULL

99990257

29

Temperature

59 / 3

0

26.67

14.92

0

NA / NA

10

NO

MONITORED

FULL

99990292

29

Temperature

5 / 3

15

22.78

19

0

NA / NA

2

NO

EVALUATED

FULL


Class BWW2 - Biological Sampling:


Benthic Macroinvertebrates:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

BM Sample Gear

BMIBI score

BMIBI Class

47b BMIBI BIT

BMIBI Pass/Fail

1242

9/6/19

70.5

47b

MS

Surber

54

Fair

62

Pass*


Fish:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

Riffle Stream?

FIBI score

FIBI Class

47b FIBI BIT

FIBI Pass/Fail

1242

9/6/19

70.5

47b

MS

Yes

58

Good

53

Pass


Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Pass (1/1)

Full

*The BMIBI score passed after using the 8 point UAV applied to single samples.

Fish

Evaluated

Pass (1/1)

Full

1

Overall

Evaluated

Pass

Full

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

Monitoring and Methods
Assessment Key Dates
9/6/2019
Biological Monitoring
1/7/2022
Monitoring Start
12/19/2024
Biological Monitoring
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
860
Other Agencies/Organizations provided monitoring data