Iowa DNR
ADBNet

Water Quality Assessments

Impaired Waters List

South River IA 04-LDM-1074

mouth (Warren Co.) to confluence with Squaw Cr. in S2 T75N R24W Warren Co.

Assessment Cycle
2022
Release Status
Final
Data Collection Period
Overall IR Category
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Unknown
Created
12/27/2021 10:06:32 AM
Updated
12/27/2021 10:14:45 AM
Assessment conducted in accordance with Iowa's 2022 IR methodology
Use Support
Class A1
Presumptive Use
Not Supported
Bacteria: Indicator Bacteria- E. coli
Support Level
Not Supported
Impairment Code
5p - Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.
Cause Magnitude
Moderate
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2008
Impairment Rationale
Geometric mean criterion exceeded
Data Source
Ambient monitoring: Iowa DNR-rivers
TMDL Priority
Tier III
Class BWW2
Not Supported
Biological: low aquatic macroinvertebrate IBI
Support Level
Not Supported
Impairment Code
5b-v - Biological - verified
Cause Magnitude
Moderate
Status
New
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2022
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 levels of indicator bacteria (E. coli) that violated 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

WQ

CY 2018-2020

10910003

South River near Ackworth

Iowa DNR

6

BIO

See Below

1239

South River

Bank Swallow Bend – Ackworth – REMAP #305

Iowa DNR

6

BIO

See Below

931

South River

Ackworth

Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples per Year (2018/ 2019/2020)

2018 Geometric Mean

2019 Geometric Mean

2020 Geometric Mean

Violates Annual Geometric Mean?

# 2018 SSM violations / SSM Violations needed for impairment

# 2019 SSM violations / SSM Violations needed for impairment

# 2020 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

10910003

6

6/6/8

528

715

365

YES

4 / NA

4 / NA

6 / 3

YES

Monitored

Not

Class A - pH

Site ID

Data Source ID

# Samples / # Years

Minimum Value

Maximum Value

Mean Value

# Violations

Violations needed for impairment

Violates Significantly >10% Rule?

Assessment Type

Support Level

10910003

6

35 / 3

6.7

8.2

7.8

0

7

NO

Monitored

Full

Class BWW2 - Conventional 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

10910003

6

Ammonia

35 / 3

0.02

0.24

0.05

NA

0 / 0

7

NO

Monitored

Full

10910003

6

Chloride

36 / 3

4.9

32

14.1

NA

0 / 0

7

NO

Monitored

Full

10910003

6

Dissolved Oxygen

36 / 3

5.4

16.9

10.1

0

NA / NA

7

NO

Monitored

Full

10910003

6

pH

35 / 3

6.7

8.2

7.8

0

NA / NA

7

NO

Monitored

Full

10910003

6

Sulfate

36 / 3

9.2

53

35.9

0

NA / NA

7

NO

Monitored

Full

10910003

6

Temperature

36 / 3

0

30.2

12.3

0

NA / NA

7

NO

Monitored

Full

Class BWW2 - Toxic Parameters:

Site ID

Data Source ID

Parameter Name

# Samples / # Years

Maximum Value

Mean Value

Median Value

# Acute / Chronic Violations

>1 Acute / Chronic Violation

Assessment Type

Support Level

10910003

6

Aluminum

14 / 3

51

5.73

0.825

0 / 0

NO

Monitored

Full

10910003

6

Arsenic

13 / 3

2

1.13

1

0 / 0

NO

Monitored

Full

10910003

6

Cadmium

13 / 3

0.07

0.03

0.02

0 / 0

NO

Monitored

Full

10910003

6

Chromium

13 / 3

1

0.6

0.7

0 / 0

NO

Monitored

Full

10910003

6

Lead

13 / 3

0.58

0.16

0.12

0 / 0

NO

Monitored

Full

10910003

6

Nickel

13 / 3

9.4

4.1

3.6

0 / 0

NO

Monitored

Full

10910003

6

Silver

13 / 3

0.025

0.025

0.025

0 / 0

NO

Monitored

Full

10910003

6

Zinc

13 / 3

3

1.88

1.8

0 / 0

NO

Monitored

Full


Class BWW2 - Biological Sampling:


Benthic Macroinvertebrates:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

BM Sample Gear

BMIBI score

BMIBI Class

47f BMIBI BIT

BMIBI Pass/ Fail

1239

9/23/20

464

47f

MS

Surber

30

Poor

51

Fail

931

8/2/18

474

47f

MS

Floating Art Sub

17

Poor

51

Fail

Fish:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

Riffle Stream?

FIBI score

FIBI Class

47f FIBI BIT

FIBI Pass/ Fail

1239

9/23/20

464

47f

MS

NA

47

Fair

36

Pass

Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Monitored

Fail (0/2)

Not

Fish

Evaluated

Pass (1/1)

Full

Assessment was monitored because the samples used to complete

Overall

Monitored

Fail

Not

5bv

the (BMIBI) assessment were collected in a recent five year period.


Monitoring and Methods
Assessment Key Dates
1/3/2018 Fixed Monitoring Start Date
12/8/2020 Fixed Monitoring End Date
9/23/2020 Biological Monitoring
8/2/2018 Biological Monitoring
Methods
230 Fixed station physical/chemical (conventional plus toxic pollutants)
315 Regional reference site approach
320 Benthic macroinvertebrate surveys
330 Fish surveys
380 Quantitative physical habitat assessment
420 Indicator bacteria monitoring