Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Shoal Creek IA 05-CHA-1342

IA/MO ln to trib S28T68NR19W Appanoose

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
Declining
Trend Comment
New Class BWW2 benthic macroinvertebrate impairment.
Created
10/27/2025 3:08:56 PM
Updated
1/6/2026 2:27:00 PM
Use Support
Class A1
Recreation - Primary contact
Not Assessed
Class BWW2
Aquatic Life - Warm Water Type 2
Not Supported
Support Level
Not Supported
Impairment Code
5b-v - Biological - verified
Cause Magnitude
Slight
Status
New
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2026
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
N/A
Cycle Added
2022
Impairment Rationale
Potential Impairment
Data Source
Ambient monitoring: Iowa DNR-continuous
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The Class BWW2 use was assessed as “not supported” based on biological sampling data and assessed as "WINOFI" based on continuous dissolved oxygen 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

1263

Shoal Creek

Exline – REMAP #289

Iowa DNR

6

BIO & WQ

See Below

218

Shoal Creek

Exline


Presumptive Class A1 - No Data


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

218

8/26/24

61.8

40a

MO

Art Sub

29

Poor

41

Fail

1263

7/29/20

66

40a

MO

Art Sub

36

Fair

41

Fail

218

7/29/20

61.8

40a

MO

Art Sub

43

Fair

41

Pass


Fish:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

Riffle Stream?

FIBI score

FIBI Class

40a FIBI BIT

FIBI Pass/Fail

218

8/26/24

61.8

40a

MO

NA

42

Fair

33

Pass

1263

7/29/20

66

40a

MO

NA

40

Fair

33

Pass

218

7/29/20

61.8

40a

MO

NA

35

Fair

33

Pass


Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Monitored

Fail (1/3)

Not

Fish

Monitored

Pass (3/3)

Full

Assessment was monitored because the samples used to complete

Overall

Monitored

Fail

Not

5bv

the assessment were collected in a recent five-year period.


Class BWW2- Continuous DO Monitoring:

Site ID

Data Source ID

# Days Monitoring (2016)

DO Criteria Type

# 2016 violations / Violations needed for impairment

Violates Annual Significantly >10% Rule?

Assessment Type

Support Level

24 hr

13/11

Yes

218

6

71

16 hr

14/11

Yes

Evaluated

WINOFI

Monitoring and Methods
Assessment Key Dates
8/26/2024
Biological Monitoring
7/29/2020
Biological Monitoring
7/7/2016
Monitoring Start
9/15/2016
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