Iowa DNR
ADBNet

Water Quality Assessments

Impaired Waters List

Soldier River IA 06-SOL-1673

mouth (S17 T80N R45W Harrison Co.) to confluence with Jordan Cr. in S16 T82N R43W Monona 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
Stable
Created
12/28/2021 6:50:04 AM
Updated
12/28/2021 6:53:22 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
Low
Cycle Added
2008
Impairment Rationale
Geometric mean criterion exceeded
Data Source
Ambient monitoring: Iowa DNR-rivers
TMDL Priority
Tier III
Class BWW1
Not Supported
Biological: low aquatic macroinvertebrate IBI
Support Level
Not Supported
Impairment Code
5b-v - Biological - verified
Cause Magnitude
Slight
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2018
Impairment Rationale
Low Biotic Index
Data Source
Biological monitoring: Iowa DNR WQMA
TMDL Priority
Tier IV
Metals: Selenium
Support Level
Not Supported
Impairment Code
5a - Pollutant-caused impairment. TMDL needed.
Cause Magnitude
Slight
Status
New
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2022
Impairment Rationale
Violations of chronic criterion
Data Source
Ambient monitoring: Iowa DNR-rivers
TMDL Priority
Tier IV
Class HH
Not Assessed
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The presumptive Class A1 use remains assessed as "not supported" due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class BWW1 use was assessed as "not supported” based on biological sampling data and due to levels of selenium that violated state water quality chronic criteria. 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

WQ

CY 2018-2020

10430002

Soldier River near Pisgah

Iowa DNR

6

BIO

See Below

183

Soldier River

Pisgah

Presumptive 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

10430002

6

0/0/8

NA

NA

552

YES

NA

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

10430002

6

36 / 3

7.1

8.6

8

0

7

NO

Monitored

Full

Class BWW1 - 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

10430002

6

Ammonia

36 / 3

0.025

1.7

0.1

NA

0 / 0

7

NO

Monitored

Full

10430002

6

Chloride

36 / 3

7.8

23

16.3

NA

0 / 0

7

NO

Monitored

Full

10430002

6

Dissolved Oxygen

36 / 3

6.7

13.7

10.3

0

NA / NA

7

NO

Monitored

Full

10430002

6

pH

36 / 3

7.1

8.6

8

0

NA / NA

7

NO

Monitored

Full

10430002

6

Sulfate

36 / 3

12

51

31

0

NA / NA

7

NO

Monitored

Full

10430002

6

Temperature

36 / 3

0

24.7

10.5

0

NA / NA

7

NO

Monitored

Full

Class BWW1 - 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

10430002

6

Aluminum

14 / 3

31

7.16

3.9

0 / 0

NO

Monitored

Full

10430002

6

Arsenic

13 / 3

4.5

2.7

2.4

0 / 0

NO

Monitored

Full

10430002

6

Cadmium

13 / 3

0.05

0.03

0.02

0 / 0

NO

Monitored

Full

10430002

6

Chromium

13 / 3

1.7

1

1

0 / 0

NO

Monitored

Full

10430002

6

Lead

13 / 3

0.25

0.13

0.12

0 / 0

NO

Monitored

Full

10430002

6

Nickel

13 / 3

6.8

3.6

3.3

0 / 0

NO

Monitored

Full

10430002

6

Selenium

13 / 3

9.2

7.1

7.4

0 / 11

YES

Monitored

Not

10430002

6

Silver

13 / 3

0.025

0.025

0.025

0 / 0

NO

Monitored

Full

10430002

6

Zinc

13 / 3

8.9

3.1

3.2

0 / 0

NO

Monitored

Full


Class BWW1 - Biological Sampling:


Benthic Macroinvertebrates:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

BM Sample Gear

BMIBI score

BMIBI Class

47e BMIBI BIT

BMIBI Pass/Fail

183

9/15/20

408.5

47e

MO

Floating ArtSub

39

Fair

54

Fail

183

8/30/2016

408.5

47e

MO

Floating ArtSub

40

Fair

54

Fail

Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Monitored

Fail (0/2)

Not

Assessment was monitored because the two samples used to complete the

Overall

Monitored

Fail

Not

5bv

assessment were collected in the last five years.


Class HH – No Data

Monitoring and Methods
Assessment Key Dates
9/15/2020 Biological Monitoring
8/30/2016 Biological Monitoring
1/9/2018 Fixed Monitoring Start Date
12/2/2020 Fixed Monitoring End Date
Methods
230 Fixed station physical/chemical (conventional plus toxic pollutants)
315 Regional reference site approach
320 Benthic macroinvertebrate surveys
420 Indicator bacteria monitoring