Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

French Creek IA 01-UIA-248

from mouth (T99N R5W S1 Allamakee County) to confluence with French Creek - West Branch (T99N R23W S23 Allamakee County)

Cycle
2024
Release Status
Final
Overall IR
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Unknown
Created
11/1/2023 8:12:45 AM
Updated
1/9/2024 11:38:29 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
High
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2008
Impairment Rationale
Geometric mean criterion exceeded
Data Source
Watershed project monitoring
TMDL Priority
Tier III
Class A2
Recreation - Secondary contact
Not Supported
Support Level
Not Supported
Impairment Code
5a - Pollutant-caused impairment. TMDL needed.
Cause Magnitude
Moderate
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2012
Impairment Rationale
Geometric mean criterion exceeded
Data Source
Watershed project monitoring
TMDL Priority
Tier III
Class BCW1
Aquatic Life - Cold Water Type 1
Fully Supported
Class HH
Human Health -
Fully Supported
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The presumptive Class A1 use and the Class A2 use both remain assessed as "not supported" based on levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class BCW1 use was assessed as "fully supported" based on biological sampling data and on the trout reproduction in Iowa streams summary prepared by the DNR Fisheries Bureau. The Class HH (fish consumption) use remains assessed as "fully supported" based on fish tissue 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

48

French Creek

French Creek SWMA - Waukon

Iowa DNR

6

BIO

See Below

539

French Creek (Main Branch)

Waukon

NEIARCD

19

WQ

CY 2012-2014

190050007

French Creek

N of Churchtown

Iowa DNR

6

BIO

See Below

1152

French Creek

N of Churchtown


Presumptive Class A1 - Indicator Bacteria: 2012-2014:

Site ID

Data Source ID

# Samples / # Years

2012 Geometric Mean

2013 Geometric Mean

2014 Geometric Mean

Annual Geometric Mean Violation

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

190050007

6

21 / 3

903

2442

622

Yes

18

86%

Yes

Evaluated

Not


Class A2 - Indicator Bacteria: 2012-2014:

Site ID

Data Source ID

# Samples / # Years

2012 Geometric Mean

2013 Geometric Mean

2014 Geometric Mean

Annual Geometric Mean Violation

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

190050007

6

21 / 3

903

2442

622

Yes

4

19%

No

Evaluated

Not


Class BCW1 - Biological Sampling:


Benthic Macroinvertebrates:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

BM Sample Gear

CBI score

CBI Class

CBI BIT

CBI Pass/Fail

48

8/3/22

10

52b

MS

Hess

75

NA

60

Pass

48

8/18/21

10

52b

MS

Hess

88

NA

60

Pass

539

8/17/21

6.1

52b

MS

Hess

76

NA

60

Pass

48

7/16/20

10

52b

MS

Hess

67

NA

60

Pass

48

8/5/19

10

52b

MS

Hess

77

NA

60

Pass

48

7/24/18

10

52b

MS

Hess

70

NA

60

Pass

Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Monitored

Pass (6/6)

Full

1

Assessment was monitored because it included multiple samples collected in the previous five years.


Class BCW1 – Trout Natural Reproduction:

Based on the January 2024 trout reproduction in Iowa streams summary prepared by the DNR Fisheries Bureau, the Class BCW1 use of French Creek was assessed as "fully supported". According to the updated summary, this stream was placed in Category I: streams that exhibit consistent natural reproduction and maintain a wild population of one or more trout species without any stocking.


Class HH - Fish Tissue Sampling:

Site ID

Biopart

Year

Species

# of samples

Avg Length (cm)

(Avg) Hg (ppm)

1152

tissue plug

2015

brown trout

5

36.0

0.05

Support Level

Full

Monitoring and Methods
Assessment Key Dates
1/1/2024
Biological Monitoring
4/3/2012
Monitoring Start
10/7/2014
Monitoring End
8/18/2021
Biological Monitoring
8/3/2022
Biological Monitoring
10/12/2015
Fish Tissue Monitoring
7/24/2018
Biological Monitoring
8/5/2019
Biological Monitoring
7/16/2020
Biological Monitoring
8/17/2021
Biological Monitoring
Methods
150
Monitoring data more than 5 years old
260
Fish tissue analysis
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys
420
Indicator bacteria monitoring