Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Fox River IA 04-FOX-995

from unnamed tributary (NW 1/4 S6 T68N R12W Davis Co.) to confluence with unnamed tributary in S29 T69N R15W Davis 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 3:09:12 PM
Updated
1/13/2026 8:52:30 AM
Use Support
Class A1
Recreation - Primary contact
Not Supported
Support Level
Not Supported
Impairment Code
5p - Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.
Cause Magnitude
Slight
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2012
Impairment Rationale
Geometric mean criterion exceeded
Data Source
Ambient monitoring: USGS
TMDL Priority
Tier III
Class BWW2
Aquatic Life - Warm Water Type 2
Not Supported
Support Level
Not Supported
Impairment Code
5b-t - Biological - tentative
Cause Magnitude
Slight
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2004
Impairment Rationale
Low Biotic Index
Data Source
Biological monitoring: Iowa DNR WQMA
TMDL Priority
Tier IV
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The presumptive Class A1 use was assessed as “not supported” due to 2009 levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class BWW2 use was assessed as "not supported" based on biological sampling data.

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

300

Fox River

Bloomfield (REMAP #48)

USGS

11

WQ

CY 2009

5494200

Fox River near West Grove, IA

USGS

11

WQ

CY 2009

5494250

Fox River near Paris, IA

USGS

11

WQ

CY 2009

5494300

Fox River at Bloomfield, IA

USGS

11

WQ

CY 2009

5494350

Fox River at Co HWY J40 near Bloomfield, IA


Presumptive Class A1 – 2009 E. coli data:

Site ID

Data Source ID

# Samples / # Years

2009 Geometric Mean

Annual Geometric Mean Violation

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

5494200

11

8 / 1

202

Yes

2

25%

Unknown (<10 samples)

Evaluated

Not

5494250

11

8 / 1

214

Yes

1

12%

Unknown (<10 samples)

Evaluated

Not

5494300

11

8 / 1

336

Yes

3

38%

Unknown (<10 samples)

Evaluated

Not

5494350

11

8 / 1

305

Yes

1

12%

Unknown (<10 samples)

Evaluated

Not


Class BWW2 - Biological Sampling:


Benthic Macroinvertebrates:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

BM Sample Gear

BMIBI score

BMIBI Class

40a BMIBI BIT

BMIBI Pass/Fail

300

7/19/22

101.1

40a

MS

Art Sub

65

Good

41

Pass

300

7/29/19

101.1

40a

MS

Art Sub

59

Good

41

Pass


Fish:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

Riffle Stream?

FIBI score

FIBI Class

40a FIBI BIT

FIBI Pass/Fail

300

7/19/22

101.1

40a

MS

NA

24

Poor

33

Fail

300

7/29/19

101.1

40a

MS

NA

34

Fair

33

Pass


Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Monitored

Pass (2/2)

Full

Fish

Evaluated

Fail (1/2)

Not

Assessment was evaluated because although the FIBI assessment used

Overall

Evaluated

Fail

Not

5bt

multiple samples collected in the last five years, it was inconclusive.


Class BWW2- Continuous DO Monitoring:

Site ID

Data Source ID

# Days Monitoring (2017/2019)

DO Criteria Type

# 2017 violations / Violations needed for impairment

# 2019 violations / Violations needed for impairment

Violates Annual Significantly >10% Rule?

Assessment Type

Support Level

24 hr

2/4

0/4

No

300

6

16/15

16 hr

1/4

0/4

No

Monitored

Full

Monitoring and Methods
Assessment Key Dates
7/29/2019
Biological Monitoring
7/19/2022
Biological Monitoring
3/2/2009
Monitoring Start
12/6/2009
Monitoring End
7/15/2019
Monitoring Start
7/29/2019
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
420
Indicator bacteria monitoring
860
Other Agencies/Organizations provided monitoring data