Iowa DNR
ADBNet

Water Quality Assessments

Impaired Waters List

Cedar River IA 02-CED-456

from confluence with McCloud Run (SW 1/4 S16 T83N R7W Linn Co.) to confluence with Bear Cr. in NE 1/4 S21 T84N R8W Linn Co. (includes East West Seminole and Northwest well fields for city of Cedar Rapids water supply).

Assessment Cycle
2020
Release Status
Final
Cycle Period
2016 - 2018
Overall IR Category
4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
Trend
Unknown
Created
8/28/2020 10:26:37 AM
Updated
10/13/2020 6:57:54 AM
Assessment conducted in accordance with Iowa's 2020 IR methodology
Use Support
Class A1
Fully Supported
Class BWW1
WINOFI
Biological: low aquatic macroinvertebrate IBI
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
Class C
Partially Supported
Nutrients: Nitrogen
Support Level
Partially Supported
Impairment Code
4a - Pollutant-caused impairment. TMDL has been completed.
Cause Magnitude
Slight
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
1998
Impairment Rationale
Significantly > 10% of samples fail to meet criterion
Data Source
Ambient monitoring: Iowa DNR-rivers
Class HH
Fully Supported
General Use
Not Assessed
Impairment Delistings
Cycle Added Class Cause Data Source Rationale
2014 Class A1 pH Ambient monitoring: USGS New data: WQ improvement (chemical / physical / bacterial)
2014 Class BWW1 pH Ambient monitoring: USGS New data: WQ improvement (chemical / physical / bacterial)
Documentation
Assessment Summary

The Class A1 use was assessed as “fully supported” based on pH monitoring data. Since this was the second consecutive cycle that pH data did not violate the pH criteria, the Class A1 pH impairment has been de-listed. The Class BWW1 use was assessed as "partially supported" based on biological sampling data. Additionally, since this was the second consecutive cycle that pH data did not violate the pH criteria, the Class BWW1 pH impairment has been de-listed. The Class C (drinking water) use was assessed as "fully supported” based on water quality monitoring; however, the Class C use will need to be assessed as "fully supported" for the next IR cycle to be moved from IR Category 4a to IR Category 1. The Class HH (fish consumption) use was assessed as "fully supported" based on water quality monitoring data. Note: A TMDL for nitrate in this segment of the Cedar River was prepared by DNR and approved by EPA in January 2007. Thus, the historic nitrate impairment in this segment is appropriate for Category 4a of Iowa’s Integrated Report.

Assessment Explanation

Sources of Data:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

USGS

11

WQ

CY 2016-2018

5464420

Cedar River at Blairs Ferry Road at Palo, IA

USGS

11

WQ

CY 2016-2016

5464480

Cedar River at Edgewood Road at Cedar Rapids, IA

CRWW

14

WQ

CY 2016-2018

99990021

Cedar River

Iowa DNR

6

BIO

See Below

951

Cedar River

Cedar Rapids – US1


Class A - pH:

Site ID

Data Source ID

# Samples / # Years

Maximum Value

Mean Value

Median Value

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

5464420

11

27 / 3

8.9

8.1

8.1

0

0%

No

Monitored

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

5464420

11

Ammonia

27 / 3

0.61

0.08

0.02

0 / 0

0% / 0%

No

Monitored

Full

5464420

11

Chloride

11 / 3

26.2

17.07

17.5

0 / 0

0% / 0%

No

Monitored

Full

5464420

11

Dissolved oxygen

27 / 3

15.5

10.8

10.5

NA / 0

NA / 0%

No

Monitored

Full

5464420

11

pH

27 / 3

8.9

8.1

8.1

0 / NA

0% / NA

No

Monitored

Full

5464420

11

Sulfate

11 / 3

34

20

21

0 / NA

0% / NA

No

Monitored

Full

5464420

11

Temperature

27 / 3

26.2

12.1

12.7

0 / 0

0% / 0%

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

% Acute/ Chronic Violations

>1 Acute / Chronic Violation

Assessment Type

Support Level

5464420

11

Chlorpyrifos-methyl

11 / 3

0.005

0.005

0.005

0 / 0

0% / 0%

No

Monitored

Full

5464480

11

Chlorpyrifos-methyl

2 / 1

0.005

0.005

0.005

0 / 0

0% / 0%

No

Evaluated

Full

5464420

11

Dieldrin

11 / 3

0.006

0.006

0.006

0 / 0

0% / 0%

No

Monitored

Full

5464480

11

Dieldrin

2 / 1

0.006

0.006

0.006

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

47c BMIBI BIT

BMIBI Pass/ Fail

951

10/9/14

6450

47c

MS/WW

Float ArtSub

51

Fair

52

Fail

951

9/19/13

6450

47c

MS/WW

ArtSub

44

Fair

52

Fail

951

9/28/12

6450

47c

MS/WW

ArtSub

41

Fair

52

Fail


Overall Assessment:

Community

Assessment Type

Assessment Result

Support Level

Earned IR Category

Actual IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Fail (0/3)

Partial

3bu

3bu

Assessment is evaluated because the drainage area of the sample site is larger than calibrated range.


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

5464420

11

Chloride

11 / 3

26.2

17.07

17.5

0

0%

No

Monitored

Full

5464420

11

Fluoride

11 / 3

210

179

180

0

0%

No

Monitored

Full

5464420

11

Inorganic nitrogen (nitrate and nitrite)

27 / 3

10.9

5.86

6.02

1

4%

No

Monitored

Full

99990021

14

Inorganic nitrogen (nitrate and nitrite)

153 / 3

12.4

6.6

6.53

12

8%

No

Monitored

Full

The Class C drinking water use was assessed as “fully supported”. Should this segment be assessed as “fully supported” for the next IR cycle, the Class C impairment will be moved from Category 4a to Category 1.


Class C - Toxic Parameters:

Site ID

Data Source ID

Parameter Name

# Samples / # Years

Maximum Value

Mean Value

Median Value

Number of Non – Detects (ND)

Mean Value > Criterion or MCL

Assessment Type

Support Level

5464420

11

Alachlor

11 / 3

0.004

0.004

0.004

11

No

All ND

Full

5464480

11

Alachlor

3 / 1

0.025

0.011

0.004

3

No

All ND

Full

5464420

11

Atrazine

11 / 3

8.14

0.955

0.086

0

No

Monitored

Full

5464480

11

Atrazine

3 / 1

4.16

1.44

0.11

0

No

Evaluated

Full

5464420

11

Carbofuran

11 / 3

0.03

0.03

0.03

11

No

All ND

Full

5464480

11

Carbofuran

2 / 1

0.03

0.03

0.03

2

No

All ND

Full

5464420

11

Simazine

11 / 3

0.004

0.004

0.003

11

No

All ND

Full

5464480

11

Simazine

3 / 1

0.025

0.0152

0.013

2

No

Evaluated

Full


Class HH-FW - Toxic Parameters:

Site ID

Data Source ID

Parameter Name

# Samples / # Years

Maximum Value

Mean Value

Median Value

Number of Non – Detects (ND)

Mean Value > Criterion or MCL

Assessment Type

Support Level

5464420

11

Dieldrin

11 / 3

0.006

0.006

0.006

11

No

All ND

Full

5464480

11

Dieldrin

2 / 1

0.006

0.006

0.006

2

No

All ND

Full


Monitoring and Methods
Assessment Key Dates
9/28/2012 Biological Monitoring
1/5/2016 Fixed Monitoring Start Date
12/26/2018 Fixed Monitoring End Date
9/19/2013 Biological Monitoring
10/9/2014 Biological Monitoring
1/1/2007 TMDL Completed
2/1/2010 TMDL Completed
Methods
230 Fixed station physical/chemical (conventional plus toxic pollutants)
270 PWS chemical monitoring (ambient water)
315 Regional reference site approach
320 Benthic macroinvertebrate surveys
150 Monitoring data more than 5 years old