Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Nishnabotna River IA 05-NSH-1412

IA/MO line to (S26 T67NR42W Fremont Co.) to confluence of E. Nishnabotna and W. Nishnabotna rivers in S2 T67N R42W Fremont 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
12/27/2021 2:37:31 PM
Updated
1/25/2022 3:28:50 PM
Assessment conducted in accordance with Iowa's 2022 IR methodology
Use Support
Class A1
Recreation
Primary contact
Not Supported
Impairments
Support Level
Not Supported
Impairment Code
5a - Pollutant-caused impairment. TMDL needed.
Cause Magnitude
High
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2012
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
Support Level
Water in Need of Further Investigation (WINOFI)
Impairment Code
3b-u - Use potentially biologically impaired based on uncalibrated IBI metrics.
Cause Magnitude
Moderate
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2006
Impairment Rationale
Low Biotic Index
Data Source
Biological monitoring: Iowa DNR WQMA
Class HH
Human Health
WINOFI
Support Level
Water in Need of Further Investigation (WINOFI)
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Slight
Status
Continuing
Source
Agriculture
Source Confidence
N/A
Cycle Added
2016
Impairment Rationale
Potential Impairment
Data Source
Ambient monitoring: USGS
Support Level
Water in Need of Further Investigation (WINOFI)
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Slight
Status
Continuing
Source
Agriculture
Source Confidence
N/A
Cycle Added
2016
Impairment Rationale
Potential Impairment
Data Source
Ambient monitoring: USGS
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The Class A1 use was assessed as "not supported" due to violations of the state criteria for indicator bacteria. The Class BWW1 use was assessed as “WINOFI” based on biological sampling data. The Class HH (fish consumption) use was assessed as “WINOFI” due to detectable levels of DDE and dieldrin in 2013 and 2014.

Assessment Explanation

Data Sources:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

Iowa DNR

6

WQ

CY 2014-2016, CY 2018-2020

10360003

Nishnabotna River near Hamburg

Iowa DNR

6

BIO

See Below

388

Nishnabotna River

Hamburg – REMAP #43

Iowa DNR

6

BIO

See Below

928

Nishnabotna River

Hamburg

Iowa DNR

6

FT

See Below

111

Nishnabotna River

at Hamburg


Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples / # Years

2014 Geo. Mean

2015 Geo. Mean

2016 Geo. Mean

Annual Geometric Mean Violation

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

10360003

6

23 / 3

900

296

1734

Yes

12

52%

Yes

Evaluated

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

10360003

6

36 / 3

7.2

8.7

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

10360003

6

Ammonia

36 / 3

0.025

0.4

0.05

NA

0 / 0

7

NO

Monitored

Full

10360003

6

Chloride

36 / 3

9

18

13

NA

0 / 0

7

NO

Monitored

Full

10360003

6

Dissolved Oxygen

36 / 3

7

13.5

10.2

0

NA / NA

7

NO

Monitored

Full

10360003

6

pH

36 / 3

7.2

8.7

8

0

NA / NA

7

NO

Monitored

Full

10360003

6

Sulfate

36 / 3

13

32

21

0

NA / NA

7

NO

Monitored

Full

10360003

6

Temperature

36 / 3

0

28.8

12.9

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

10360003

6

Aluminum

14 / 3

23

5.44

2.7

0 / 0

NO

Monitored

Full

10360003

6

Arsenic

13 / 3

3.6

2.3

2.3

0 / 0

NO

Monitored

Full

10360003

6

Cadmium

13 / 3

0.025

0.025

0.025

0 / 0

NO

Monitored

Full

10360003

6

Chromium

13 / 3

1.1

0.6

0.7

0 / 0

NO

Monitored

Full

10360003

6

Lead

13 / 3

0.23

0.1

0.08

0 / 0

NO

Monitored

Full

10360003

6

Nickel

13 / 3

3.7

2.8

2.8

0 / 0

NO

Monitored

Full

10360003

6

Silver

13 / 3

0.025

0.025

0.025

0 / 0

NO

Monitored

Full

10360003

6

Zinc

13 / 3

4.1

2

2.2

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

47m BMIBI BIT

BMIBI Pass/Fail

388

10/6/20

2818

47m

MO

Floating Art Sub

29

Poor

54

Fail

928

8/13/18

2807

47m

MO

Floating Art Sub

45

Fair

54

Fail

928

9/6/16

2807

47m

MO

Floating Art Sub

46

Fair

54

Fail

Fish:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

Riffle Stream?

FIBI score

FIBI Class

47m FIBI BIT

FIBI Pass/Fail

388

10/6/20

2818

47m

MO

NA

30

Fair

31

Pass

Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Fail (0/3)

Not

The FIBI score passed using the 7 point UAV applied to single samples.

Fish

Evaluated

Pass (1/1)

Full

Assessment was evaluated because the drainage areas of the sample sites

Overall

Evaluated

Fail

WINOFI

3bu

were larger than the calibrated range.

Class BWW1- Continuous DO Monitoring:

Site ID

Data Source ID

# Days Monitoring (2016/2017/2018/ 2019/2020)

DO Criteria Type

# 2016 violations / Violations needed for impairment

# 2017 violations / Violations needed for impairment

# 2018 violations / Violations needed for impairment

# 2019 violations / Violations needed for impairment

# 2020 violations / Violations needed for impairment

Violates Annual Significantly >10% Rule?

Assessment Type

Support Level

24 hr

NA

NA

NA

NA

0/4

No

388

6

0/0/0/0/14

16 hr

NA

NA

NA

NA

0/4

No

Evaluated

Full


Class HH - Fish Tissue Sampling:

Site ID

Biopart

Year

Species

# in sample / # of samples

Avg Length (cm)

(Avg) Hg (ppm)

Chlordane (ppm)

Sum PCBs (ppm)

111

whole

2016

common carp

5

53

0.05

0.06

0.06

Support Level

Full

Class HH – Historic Assessment:

The results of USGS monitoring from 2012 and 2014 showed one of the 33 samples (3%) analyzed for DDE and three of the 33 samples (9%) analyzed for Dieldrin exceeded criteria. The sample collected on January 16, 2013 at USGS station 6810000 (near Hamburg) had a detectable level of DDE of 0.003 ug/l, thus exceeding the HH-fish criterion of 0.0022 ug/l. Levels of DDE the remainder of the samples at this monitoring stations were reported as less than the levels of detection (0.002 ug/l and 0.005 ug/l). The samples collected on June 10, 2014, July 15, 2014 and September 16, 2014 at USGS station 06810000 (near Hamburg) had detectable levels of dieldrin of 0.004 ug/l, 0.003 ug/l and 0.003 ug/l respectively, thus exceeding the HH-fish criterion of 0.00054 ug/l. Levels of dieldrin the remainder of the samples at this monitoring stations were reported as less than the level of detection (0.008 ug/l). According to DNR’s assessment/listing methodology, if the average level of a toxic metal or pesticide is greater than its respective human health criterion, impairment ("WINOFI") of the Human Health use is indicated. The number of samples with detectable levels of DDE and dieldrin at these monitoring stations (1/33 and 3/33), however, is too few and the method detection level is far too high (~16 times greater than the HH criterion for dieldrin) to allow calculation of a meaningful summary statistic (e.g., mean) for DDE and dieldrin at this monitoring station. Based on sampling that shows detectable levels of DDE and dieldrin, however, the Human Health designated use will be considered (evaluated) as “WINOFI.”

Monitoring and Methods
Assessment Key Dates
9/6/2016
Biological Monitoring
8/13/2018
Biological Monitoring
2/2/2012
Fixed Monitoring Start Date
9/16/2014
Fixed Monitoring End Date
8/19/2016
Fish Tissue Monitoring
10/1/2014
Fixed Monitoring Start Date
12/6/2016
Fixed Monitoring End Date
1/8/2018
Fixed Monitoring Start Date
12/1/2020
Fixed Monitoring End Date
10/6/2020
Biological Monitoring
Methods
150
Monitoring data more than 5 years old
222
Non-fixed-station monitoring (conventional during key seasons and flows)
230
Fixed station physical/chemical (conventional plus toxic pollutants)
260
Fish tissue analysis
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys
420
Indicator bacteria monitoring