Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Des Moines River IA 04-LDM-1011

from Ottumwa dam (S24 T72N R14W Wapello Co.) to confluence with Cedar Cr in S33 T75N R17W Mahaska Co.

Assessment Cycle
2020
Release Status
Final
Data Collection Period
Overall IR Category
2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
Trend
Unknown
Created
6/9/2020 1:19:50 PM
Updated
10/16/2020 11:42:44 AM
Assessment conducted in accordance with Iowa's 2020 IR methodology
Use Support
Class A1
Recreation
Primary contact
Fully Supported
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
Slight
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2014
Impairment Rationale
Low Biotic Index
Data Source
Biological monitoring: Iowa DNR WQMA
Support Level
Water in Need of Further Investigation (WINOFI)
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Moderate
Status
Continuing
Source
Hydromodification: Low Flow
Source Confidence
Moderate
Cycle Added
2018
Impairment Rationale
Non Pollutant-caused fish kill
Data Source
Fish kill investigation: Iowa DNR
Class C
Drinking Water
Fully Supported
Class HH
Human Health
Not Assessed
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 “fully supported” based on water quality monitoring data. The Class BWW1 use was assessed as "partially supported” based on biological sampling data and based on the results of a fish kill investigation. The Class C use remains assessed as "fully supported" based on water quality monitoring data. All other designated uses were "not assessed".

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

10900003

Des Moines River US of Ottumwa at Co Rd T67 Bridge at Chillicothe

Iowa DNR

6

BIO

See Below

955

Des Moines River – Ottumwa - US

Iowa DNR

6

BIO

See Below

1156

Des Moines River – Chillicothe REMAP #454


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

10900002

6

22 / 3

86

40

100

No

3

14%

No

Evaluated

Full


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

10900002

6

33 / 3

8.7

8.2

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

10900002

6

Ammonia

33 / 3

0.45

0.1

0.05

0 / 0

0% / 0%

No

Evaluated

Full

10900002

6

Chloride

33 / 3

91

49

43

0 / 0

0% / 0%

No

Evaluated

Full

10900002

6

Dissolved oxygen

33 / 3

17

10.6

10.1

NA / 0

NA / 0%

No

Evaluated

Full

10900002

6

pH

33 / 3

8.7

8.2

8.2

0 / NA

0% / NA

No

Evaluated

Full

10900002

6

Sulfate

33 / 3

130

78

82

0 / NA

0% / NA

No

Evaluated

Full

10900002

6

Temperature

33 / 3

29.1

12.8

11.8

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

BMIBI BIT

BMIBI Pass/ Fail

1156

8/22/17

13200

40a

MS/WW

Float ArtSub

64

Good

41

Pass

955

10/8/12

13257

47f

MS/WW

ArtSub

15

Poor

51

Fail

Fish:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/Thermal

Riffle Stream?

FIBI score

FIBI Class

40a FIBI BIT

FIBI Pass/ Fail

1156

8/22/17

13200

40a

MS/WW

NA

32

Fair

33

Pass

Overall:

Community

Assessment Type

Assessment Result

Support Level

Earned IR Category

Actual IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Fail (1/2)

Partial

Fish

Evaluated

Pass (1/1)

Full

FIBI passed with 7 point FIBI UAV applied to single samples.

Overall

Evaluated

Fail

Partial

3bu

3bu

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


Class BWW1 – Fishkill Assessment:

The Class BWW1 use assessment based on the 2017 fish kill placed this segment in Category 3b. Because the cause of the fish kill was not identified, or the fish kill was attributed to a non-pollutant cause (e.g., winterkill), the assessment type is “evaluated.” Segments assessed using “evaluated” assessments are placed in Category 3b and are added to the state list of waters in need of further investigation. If no additional fish kills are reported in the segment for a 10 year period (2027), the Category will be changed from 3b to 3a (water not assessed).

Details about the 2016 fish kill can be found here:https://programs.iowadnr.gov/fishkill/Events/944

Class C - Conventional Parameters:

Site ID

Data Source ID

Parameter Name

# Samples / # Years

Maximum Value

Mean Value

Median Value

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

10620001

6

Chloride

33 / 3

91

49

43

0

0%

No

Evaluated

Full

10620001

6

Inorganic nitrogen (nitrate and nitrite)

33 / 3

14

4

3.4

2

6%

No

Evaluated

Full

Class C - Toxic Parameters:

Site ID

Data Source ID

Parameter Name

# Samples / # Years

Maximum Value

Mean Value

Median Value

Number of Non - Detects

Mean Value > Criterion or MCL

Assessment Type

Support Level

10620001

6

Alachlor

32 / 3

0.1

0.04

0.025

NA

No

Evaluated

Full

10620001

6

Atrazine

26 / 3

2

0.43

0.2

NA

No

Evaluated

Full

10620001

6

Carbofuran

26 / 3

0.1

0.1

0.1

NA

No

Evaluated

Full

10620001

6

Cyanazine

26 / 3

0.1

0.1

0.1

NA

No

Evaluated

Full


Class HH - No Data


Monitoring and Methods
Assessment Key Dates
10/8/2012
Biological Monitoring
1/5/2012
Fixed Monitoring Start Date
9/14/2014
Fixed Monitoring End Date
8/4/2017
Fish Kill
8/22/2017
Biological Monitoring
Methods
120
Surveys of fish and game biologists/other professionals
140
Incidence of spills and/or fish kills
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
330
Fish surveys
420
Indicator bacteria monitoring