Iowa DNR
ADBNet

Water Quality Assessments

Impaired Waters List

Little Sioux River IA 06-LSR-1564

mouth (Harrison Co.) to confluence with Maple R. near Turin in S17 T83N R44W 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
Unknown
Created
12/28/2021 6:07:06 AM
Updated
12/28/2021 6:09:57 AM
Assessment conducted in accordance with Iowa's 2022 IR methodology
Use Support
Class A1
Not Supported
Bacteria: Indicator Bacteria- E. coli
Support Level
Not Supported
Impairment Code
5a - Pollutant-caused impairment. TMDL needed.
Cause Magnitude
Moderate
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2012
Impairment Rationale
Geometric mean criterion exceeded
Data Source
Ambient monitoring: USGS
TMDL Priority
Tier III
Class BWW1
Not Supported
Metals: Selenium
Support Level
Not Supported
Impairment Code
5a - Pollutant-caused impairment. TMDL needed.
Cause Magnitude
Slight
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2020
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 Class A1 use was assessed as "not supported" due to violations of Iowa’s water quality criteria for indicator bacteria (E. coli). The Class BWW1 use remains assessed as “not supported” due to violations of Iowa’s water quality chronic criteria for selenium. 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

10670003

Little Sioux River near Turin

Iowa DNR

6

BIO

See Below

922

Little Sioux River

Turin

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

10670003

6

0/0/7

NA

NA

164

YES

NA

NA

3 / 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

10670003

6

36 / 3

7

8.6

8.1

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

10670003

6

Ammonia

36 / 3

0.025

1.6

0.1

NA

0 / 0

7

NO

Monitored

Full

10670003

6

Chloride

36 / 3

13

27

18

NA

0 / 0

7

NO

Monitored

Full

10670003

6

Dissolved Oxygen

36 / 3

6.7

15.1

10.5

0

NA / NA

7

NO

Monitored

Full

10670003

6

pH

36 / 3

7

8.6

8.1

0

NA / NA

7

NO

Monitored

Full

10670003

6

Sulfate

36 / 3

4.1

86

50.1

0

NA / NA

7

NO

Monitored

Full

10670003

6

Temperature

36 / 3

0

26.6

11.1

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

10670003

6

Aluminum

14 / 3

15

4.54

2.95

0 / 0

NO

Monitored

Full

10670003

6

Arsenic

13 / 3

3.6

2.1

1.9

0 / 0

NO

Monitored

Full

10670003

6

Cadmium

13 / 3

0.07

0.03

0.02

0 / 0

NO

Monitored

Full

10670003

6

Chromium

13 / 3

1.5

0.8

0.8

0 / 0

NO

Monitored

Full

10670003

6

Lead

13 / 3

0.2

0.1

0.1

0 / 0

NO

Monitored

Full

10670003

6

Nickel

13 / 3

5.3

3.5

3.2

0 / 0

NO

Monitored

Full

10670003

6

Silver

13 / 3

0.025

0.025

0.025

0 / 0

NO

Monitored

Full

10670003

6

Zinc

13 / 3

3.4

2.1

1.9

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

47d BMIBI BIT

BMIBI Pass/Fail

922

9/18/19

4426

47d

MO

Floating Art Sub

35

Fair

54

Fail

922

10/7/15

4426

47d

MO

Floating Art Sub

60

Good

54

Pass

922

7/31/13

4426

47d

MO

Floating Art Sub

57

Good

54

Pass

Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Pass (2/3)

Full

Assessment was evaluated because the drainage area of the site was

Overall

Evaluated

Pass

Full

1

greater than the calibrated range.


Class HH – No Data

Monitoring and Methods
Assessment Key Dates
12/2/2020 Fixed Monitoring End Date
7/31/2013 Biological Monitoring
10/7/2015 Biological Monitoring
1/9/2018 Fixed Monitoring Start Date
9/18/2019 Biological Monitoring
Methods
150 Monitoring data more than 5 years old
230 Fixed station physical/chemical (conventional plus toxic pollutants)
315 Regional reference site approach
320 Benthic macroinvertebrate surveys
420 Indicator bacteria monitoring