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.

Cycle
2020
Release Status
Final
Overall IR
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Unknown
Created
9/10/2020 10:50:29 AM
Updated
10/12/2020 9:54:14 AM
Use Support
Class A1
Recreation - Primary contact
Partially Supported
Support Level
Partially 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
Partially Supported
Support Level
Partially 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 Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Slight
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2004
Impairment Rationale
Potential Impairment
Data Source
Biological monitoring: Iowa DNR WQMA
General Use
General Use water -
Not Assessed
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The presumptive Class A1 primary contact recreation use remains assessed as “partially supported” due to 2009 levels of indicator bacteria that exceeded state water quality criteria. The Class BWW2 aquatic life use remains assessed as "partially supported" based on 2010 and 2013 biological sampling data and on 2002 continuous water quality monitoring data. All other designated uses were "not assessed".

Assessment Explanation

Sources of Data:

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

Iowa DNR

6

BIO

See Below

756

Fox River

Drakesville

Iowa DNR

6

BIO

See Below

757

Fox River

West Grove – ID#2

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

Class A1 - Indicator Bacteria:

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

Partial

5494250

11

8 / 1

214

Yes

1

12%

Unknown (<10 samples)

Evaluated

Partial

5494300

11

8 / 1

336

Yes

3

38%

Unknown (<10 samples)

Evaluated

Partial

5494350

11

8 / 1

305

Yes

1

12%

Unknown (<10 samples)

Evaluated

Partial

Class BWW2 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/Thermal

BM Sample Gear

BMIBI score

BMIBI Class

40a BMIBI BIT

BMIBI Pass/ Fail

300

7/15/13

101

40a

MS/WW

ArtSub

16

Poor

41

Fail

757

10/4/10

64

40a

MS/WW

Hess

49

Fair

41

Pass

757

10/4/10

64

40a

MS/WW

ArtSub

55

Fair

41

Pass

Fish:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/Thermal

Riffle Stream?

FIBI score

FIBI Class

40a FIBI BIT

FIBI Pass/ Fail

300

7/15/13

101

40a

MS/WW

NA

20

Poor

33

Fail

756

10/5/10

74

40a

MS/WW

NA

30

Fair

33

Fail

757

10/4/10

64

40a

MS/WW

NA

24

Poor

33

Fail

Overall:

Community

Assessment Type

Assessment Result

Support Level

Earned IR Category

Actual IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Pass (2/3)

Full

Fish

Evaluated

Fail (0/3)

Partial

Overall

Evaluated

Fail

Partial

3bc

5bt

Assessment is evaluated because it included samples not collected in the last five years.

Class BWW2 – Continuous Monitoring:

As part of the REMAP project, diurnal dissolved oxygen and temperature monitoring conducted during July 2002 found dissolved oxygen levels sagging to approximately 4.2 mg/L during night hours. Additional sampling data are needed to evaluate the extent, causes and sources of this water quality problem. Stream physical habitat assessment found excessive sediment deposits and a lack of instream cover that could also contribute to the biological impairment. The wide-shallow channel probably contributes to observed high stream temperature (>36C) and high rates of biological community respiration and primary production.

Monitoring and Methods
Assessment Key Dates
10/4/2010
Biological Monitoring
10/5/2010
Biological Monitoring
7/15/2013
Biological Monitoring
3/2/2009
Non-fixed Monitoring Start Date
12/6/2009
Non-fixed Monitoring End Date
Methods
150
Monitoring data more than 5 years old
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys
420
Indicator bacteria monitoring