2022 Final assessment for Cedar River

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

2022

Release Status

Final

Data Collection Period

For purposes of developing stream/river water quality assessments for integrated reporting, three years of water quality data are typically used for both conventional pollutant parameters (e.g., indicator bacteria) and the less frequently monitored toxic parameters (e.g., toxic metals). Since the 2004 IR cycle, DNR has used a three-year data gathering period for streams, rivers, and beaches. For most assessments, the use of three years of data increases the number of samples upon which the decision on use support is based and helps address the problem of weather-related year-to-year fluctuations in water quality.

Due to the lower sampling frequency in Iowa’s ambient lake, biological, fish kill, and fish tissue monitoring programs, five years of data are used for developing IR assessments and for identifying Section 303(d) listings.

Data Type	Data Timeframe
Beach Sampling Data	CY 2018 - 2020
Stream/River Water Quality Data	CY 2018 - 2020
Lake Water Quality Data	CY 2016 - 2020
Biological Sampling Data	CY 2016 - 2020*
Fish Kill Data	CY 2016 - 2020
Fish Tissue Sampling Data	CY 2016 - 2020
Continuous Dissolved Oxygen Sampling Data	CY 2016 - 2020
*Biological sites sampled in both 2015 and 2019 were also assessed.

Overall IR Category: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown

Created: 12/29/2021 9:38:23 AM
Updated: 1/19/2022 2:52:50 PM

Assessment conducted in accordance with Iowa's 2022 IR methodology

Use Support

Class A1

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not Supported

Impairment Code

4a - Pollutant-caused impairment. TMDL has been completed.

Cause Magnitude

Slight

Status

New

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2022

Impairment Rationale

Single-sample maximum criterion exceeded in significantly > 10% of samples

Data Source

Ambient monitoring: municipal water supply

Class BWW1

Not Supported

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

Metals: Copper

Support Level

Not Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

Moderate

Status

New

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2022

Impairment Rationale

Violations of acute criterion

Data Source

Ambient monitoring: municipal water supply

TMDL Priority

Tier IV

Class C

Fully Supported

Class HH

Fully Supported

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use was assessed as “not supported” due to levels of indicator bacteria (E. coli) that slightly exceed state water quality criteria. The Class BWW1 use was assessed as "not supported" based on biological sampling data and on violations of the acute/chronic copper water quality criteria. The Class C (drinking water) and the Class HH (fish consumption) uses were 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 and a TMDL for E. coli in this segment of the Cedar River was prepared by DNR and approved by EPA in January 2010.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
CRWW	14	WQ	CY 2018-2020	99990021	Cedar River
USGS	11	WQ	CY 2018-2020	5464420	Cedar River at Blairs Ferry Road at Palo, IA
Iowa DNR	6	BIO	See Below	1260	Cedar River	Cedar Rapids – REMAP #410

Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples per Year (2018/ 2019/2020)

2018 Geometric Mean

2019 Geometric Mean

2020 Geometric Mean

Violates Annual Geometric Mean?

# 2018 SSM violations / SSM Violations needed for impairment

# 2019 SSM violations / SSM Violations needed for impairment

# 2020 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

99990021

35/35/33

121

15 / 7

7 / 7

4 / 7

YES

Monitored

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
5464420	11	34 / 3	7.4	8.8	8.1	0	7	NO	Monitored	Full
99990021	14	153 / 3	7.1	9.2	8.2	2	21	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
5464420	11	Ammonia	33 / 3	0.005	0.61	0.06	NA	0 / 0	7	NO	Monitored	Full
99990021	14	Ammonia	147 / 3	0.01	0.8	0.1	NA	0 / 1	20	NO	Monitored	Full
5464420	11	Chloride	13 / 3	9.2	26.2	18.6	NA	0 / 0	4	NO	Monitored	Full
99990021	14	Chloride	147 / 3	2.5	62	22.3	NA	0 / 0	20	NO	Monitored	Full
5464420	11	Dissolved Oxygen	34 / 3	6.3	16	11.1	0	NA / NA	7	NO	Monitored	Full
5464420	11	pH	34 / 3	7.4	8.8	8.1	0	NA / NA	7	NO	Monitored	Full
99990021	14	pH	153 / 3	7.1	9.2	8.2	2	NA / NA	21	NO	Monitored	Full
5464420	11	Sulfate	13 / 3	8.7	31.7	21.8	0	NA / NA	4	NO	Monitored	Full
99990021	14	Sulfate	147 / 3	5.74	48.48	24.91	0	NA / NA	20	NO	Monitored	Full
5464420	11	Temperature	34 / 3	-0.1	26.6	11.8	0	NA / NA	7	NO	Monitored	Full
99990021	14	Temperature	153 / 3	-0.72	27.94	11.73	0	NA / NA	21	NO	Monitored	Full

Class BWW1 Metals - 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
5464420	11	Chloropyrifos	8 / 2	0.04	0.01	0.005	0 / 0	NO	Evaluated	Full
99990021	14	Copper	150 / 3	66.3	2.6	1.4	2 / 4	YES	Monitored	Not
5464420	11	Dieldrin	8 / 2	0.006	0.006	0.006	0 / 0	NO	Evaluated	Full
99990021	14	Lead	150 / 3	6.6	0.9	0.6	0 / 1	NO	Monitored	Full
99990021	14	Zinc	150 / 3	67.6	8.7	6.9	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	47c BMIBI BIT	BMIBI Pass/Fail
1260	9/22/20	6450	47c	MS	Floating Art Sub	35	Fair	52	Fail

Fish:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47c FIBI BIT	FIBI Pass/Fail
1260	9/23/20	6450	47c	MS	Undetermined	79	Excellent	44	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (0/1)	Not
Fish	Evaluated	Pass (1/1)	Full		Assessment was evaluated because the drainage area of the sample site
Overall	Evaluated	Fail	WINOFI	3bu	was greater than the calibrated range.

Class C - Conventional Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Minimum Value	Maximum Value	Mean Value	Median Value	# Violations	Violates Significantly >10% Rule?	Assessment Type	Support Level
5464420	11	Chloride	13 / 3	9.2	26.2	18.6	18.4	0	NO	Monitored	Full
99990021	14	Chloride	147 / 3	2.5	62	22.3	20.9	0	NO	Monitored	Full
5464420	11	Fluoride	13 / 3	150	220	191	190	0	NO	Monitored	Full
5464420	11	Nitrate + Nitrite	33 / 3	1.46	9.73	5.14	5.15	0	NO	Monitored	Full
99990021	14	Nitrate	149 / 3	0.05	10.6	5.3	5.7	1	NO	Monitored	Full
99990021	14	Nitrite	148 / 3	0.005	0.09	0.01	0.005	0	NO	Monitored	Full
5464420	11	pH	34 / 3	7.4	8.8	8.1	8.1	0	NO	Monitored	Full
99990021	14	pH	153 / 3	7.1	9.2	8.2	8.1	2	NO	Monitored	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
5464420	11	Alachlor	8 / 2	0.004	0.004	0.004	8	NO	Evaluated	Full
5464420	11	Atrazine	8 / 2	8.14	1.26	0.16	0	NO	Evaluated	Full
5464420	11	Carbofuran	8 / 2	0.03	0.03	0.03	8	NO	Evaluated	Full
5464420	11	Simazine	8 / 2	0.03	0.01	0.004	7	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	Mean Value > Criterion or MCL	Assessment Type	Support Level
99990021	14	Copper	150 / 3	66.3	2.6	1.4	71	NO	Monitored	Full
5464420	11	Dieldrin	8 / 2	0.006	0.006	0.006	8	NO	Evaluated	Full
99990021	14	Zinc	150 / 3	67.6	8.7	6.9	31	NO	Monitored	Full

Monitoring and Methods

Assessment Key Dates

1/2/2018	Fixed Monitoring Start Date
12/29/2020	Fixed Monitoring End Date
9/23/2020	Biological Monitoring
1/24/2007	TMDL Completed
2/26/2010	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

Water Quality Assessments

Impaired Waters List

Cedar River IA 02-CED-456

Assessment Summary

Assessment Explanation

Assessment Key Dates

Methods