Iowa DNR
Iowa DNR

ADBNet

Water Quality Assessments
Impaired Waters List

Cedar River IA 02-CED-452

from Hwy 30 bridge at Cedar Rapids (S9 T82N R6W Linn Co) to confluence with Prairie Cr. in the SE 1/4 S34 T83N R7W Linn Co.

Overall IR
4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
Trend
Unknown
Created
8/28/2020 8:29:24 AM by
Updated
10/16/2020 7:31:53 AM by
Use Support
Class A1
Recreation - Primary contact
Partially Supported
Support Level
Partially Supported
Impairment Code
4a - Pollutant-caused impairment. TMDL has been completed.
Cause Magnitude
Slight
303(d) Listing Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2004
Impairment Rationale
Geometric mean criterion exceeded
Data Source
Ambient monitoring: Iowa DNR-rivers
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
303(d) Listing 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
No delistings for this assessment cycle.
Documentation
Assessment Summary

The Class A1 use remains assessed as "partially supported" due to levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class BWW1 use remains assessed as “partially supported” based on the biological sampling data. The Class HH use remains assessed as “fully supported” based on fish tissue sampling data. Note: A TMDL for indicator bacteria in this segment of Cedar River was prepared and approved by EPA in February 2010. The approval of this TMDL moved the bacterial impairment for this segment from Iowa's list of Section 303(d) waters (Category 5a of the IR) to IR Category 4a.

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 2014-16

10570001

Cedar River DS of Cedar Rapids (DS1)

Site located in Seg. 451 and no longer used for this segment.

Iowa DNR

6

BIO

See Below

503

Cedar River

Bertram – REMAP #185

Iowa DNR

6

FT

See Below

16

Cedar River

At Cedar Rapids


Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples / # Years

2014 Geometric Mean

2015 Geometric Mean

2016 Geometric Mean

Annual Geometric Mean Violation

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

10570001

6

23 / 3

131

277

233

Yes

10

43%

Yes

Monitored

Partial


Class BWW1 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/Thermal

BM Sample Gear

BMIBI score

BMIBI Class

47f BMIBI BIT

BMIBI Pass/ Fail

503

10/10/05

6829

47f

MS/WW

ArtSub

47

Fair

51

Fail

503

9/1/05

6829

47f

MS/WW

ArtSub

19

Poor

51

Fail

Overall Assessment:

Community

Assessment Type

Assessment Result

Support Level

Earned IR Category

Actual IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Fail (0/2)

Partial

3bu

3bu

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

16

8/16/2016

channel catfish

fillet

3

<0.02

No

<0.06

No

0.12

No

Monitored

Full

16

8/3/2015

largemouth bass

plug

5

0.050

No

Monitored

Full

16

8/3/2015

channel catfish

fillet

5

<0.02

No

0.26

Yes

0.09

No

Monitored

Partial

Monitoring and Methods
Assessment Key Dates
9/1/2005
Biological Monitoring
10/10/2005
Biological Monitoring
8/3/2015
Fish Tissue Monitoring
1/2/2014
Fixed Monitoring Start Date
12/8/2016
Fixed Monitoring End Date
8/16/2016
Fish Tissue Monitoring
2/1/2010
TMDL Completed
Methods
150
Monitoring data more than 5 years old
230
Fixed station physical/chemical (conventional plus toxic pollutants)
260
Fish tissue analysis
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
420
Indicator bacteria monitoring