Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Little Sioux River IA 06-LSR-1573

from confluence with Willow Cr. (S17 T94N R36W Clay Co.) to east corporate limit of Spencer at west line of S17 T96N R36W Clay Co.

Cycle
2020
Release Status
Final
Overall IR
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Stable
Created
9/21/2020 3:06:26 PM
Updated
10/19/2020 7:36:18 AM
Use Support
Class A1
Recreation - Primary 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
Low
Cycle Added
2008
Impairment Rationale
Geometric mean criterion exceeded
Data Source
Ambient monitoring: Iowa DNR-rivers
TMDL Priority
Tier III
Class BWW1
Aquatic Life - Warm Water Type 1
WINOFI
Impairment Code
3b-u - Use potentially biologically impaired based on uncalibrated IBI metrics.
Cause Magnitude
Slight
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2008
Impairment Rationale
Low Biotic Index
Data Source
Biological monitoring: Iowa DNR WQMA
Class HH
Human Health -
Fully Supported
General Use
General Use water -
Not Assessed
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The 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 remains assessed as "partially supported" based on biological sampling data. The Class HH use remains assessed as "fully supported" based on fish tissue sampling.

Assessment Explanation

Sources of Data:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

Iowa DNR

6

WQ

CY 2012-2014

10210003

Little Sioux River

DS of Spencer (DS1)

Iowa DNR

6

BIO

See Below

924

Little Sioux River

Spencer – DS1

Iowa DNR

6

BIO

See Below

481

Little Sioux River

Spencer – REMAP #129

Iowa DNR

6

FT

See Below

183

Little Sioux River

At Gillet Grove


Class A1 - Indicator Bacteria:

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

10210003

6

22 / 3

1181

1805

895

Yes

19

86%

Yes

Evaluated

Not


Class A1 - pH:

Site ID

Data Source ID

# Samples / # Years

Maximum Value

Mean Value

Median Value

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

10210003

6

32 / 3

8.7

8.13

8.2

0

0%

No

Evaluated

Full


Class BWW1 - Conventional Parameters:

Site ID

Data Source ID

Parameter Name

# Samples / # Years

Maximum Value

Mean Value

Median Value

# Acute / Chronic Violations

% Acute/ Chronic Violations

Significantly >10% Violations

Assessment Type

Support Level

10210003

6

Ammonia

32 / 3

1.3

0.15

0.05

0 / 0

0% / 0%

No

Evaluated

Full

10210003

6

Chloride

33 / 3

57

33.3

32

0 / 0

0% / 0%

No

Evaluated

Full

10210003

6

Dissolved oxygen

33 / 3

16.5

11.1

10.6

NA / 0

NA / 0%

No

Evaluated

Full

10210003

6

pH

32 / 3

8.7

8.13

8.2

0 / NA

0% / NA

No

Evaluated

Full

10210003

6

Sulfate

33 / 3

180

101

100

0 / NA

0% / NA

No

Evaluated

Full

10210003

6

Temperature

33 / 3

27.3

11.7

11.6

0 / 0

0% / 0%

No

Evaluated

Full


Class BWW1 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/ Thermal

BM Sample Gear

BMIBI score

BMIBI Class

47a BMIBI BIT

BMIBI Pass/ Fail

924

9/8/14

1104

47a

MO/WW

ArtSub

38

Fair

54

Fail

924

10/8/13

1104

47a

MO/WW

ArtSub

44

Fair

54

Fail

Fish:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/ Thermal

Riffle Stream?

FIBI score

FIBI Class

47a FIBI BIT

FIBI Pass/ Fail

481

9/6/05

1109

47a

MO/WW

NA

33

Fair

43

Fail

Overall:

Community

Assessment Type

Assessment Result

Support Level

Earned IR Category

Actual IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Fail (0/2)

Partial

Fish

Evaluated

Fail (0/1)

Partial

Overall

Evaluated

Fail

Partial

3bu

3bu

Assessment is evaluated because the drainage areas of the sample sites were larger than the calibrated range.


Class HH – Fish Tissue Sampling:

Site ID

Date

Species Name

Biopart

# in sample

chlordane result

chlordane violation (>0.6)?

PCBs result

PCBs violation (>0.2)?

Hg result

Hg violation (>0.3)?

Assessment Type

Support Level

183

10/2/2015

walleye

plug

5

0.174

No

Monitored

Full

183

9/22/2011

largemouth bass

plug

5

0.289

No

Evaluated

Full

183

9/14/2011

channel catfish

fillet

3

<0.03

No

<0.09

No

0.115

No

Evaluated

Full

Monitoring and Methods
Assessment Key Dates
1/9/2012
Fixed Monitoring Start Date
9/8/2014
Fixed Monitoring End Date
9/14/2011
Fish Tissue Monitoring
9/6/2005
Biological Monitoring
10/8/2013
Biological Monitoring
9/8/2014
Biological Monitoring
10/2/2015
Fish Tissue Monitoring
9/22/2011
Fish Tissue Monitoring
Methods
150
Monitoring data more than 5 years old
210
Fixed station physical/chemical monitoring (conventional pollutants only)
260
Fish tissue analysis
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys
420
Indicator bacteria monitoring