2024 Pending 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

2024

Release Status

Pending

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 2020 - 2022
Stream/River Water Quality Data	CY 2020 - 2022
Lake Water Quality Data	CY 2018 - 2022
Biological Sampling Data	CY 2018 - 2022*
Fish Kill Data	CY 2018 - 2022
Fish Tissue Sampling Data	CY 2018 - 2022
Continuous Dissolved Oxygen Sampling Data	CY 2018 - 2022
*Biological sites sampled in both 2017 and 2021 were also assessed.

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

Created: 11/1/2023 8:13:10 AM
Updated: 1/17/2024 12:41:13 PM

Assessment conducted in accordance with Iowa's 2024 IR methodology.

Use Support

Class A1

Fully Supported

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

Continuing

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 "fully supported supported" based on water quality monitoring data. 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 2020-2022	99990021	Cedar River
Iowa DNR	6	WQ	CY 2021-2022	14000348	Cedar River
USGS	11	WQ	CY 2020-2022	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 (2020/ 2021/2022)

2020 Geometric Mean

2021 Geometric Mean

2022 Geometric Mean

Violates Annual Geometric Mean?

# 2020 SSM violations / SSM Violations needed for impairment

# 2021 SSM violations / SSM Violations needed for impairment

# 2022 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

99990021

33/35/36

4 / 7

2 / 7

4 / 7

Mon

Full

Class A1 - 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
14000348	6	10 / 2	8.03	8.85	8.53	0	3	NO	Mon	Full
5464420	11	49 / 3	7.5	8.8	8.3	0	9	NO	Mon	Full
99990021	14	157 / 3	6.93	9.57	7.77	1	22	NO	Mon	Full

Class BWW1 - Binomial 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	Chloride	13 / 2	9.8	36.6	24.9	NA	0 / 0	4	NO	Mon	Full
99990021	14	Chloride	149 / 3	12	57	28	NA	0 / 0	21	NO	Mon	Full
14000348	6	Dissolved Oxygen	10 / 2	7.7	16.2	13	0	NA / NA	3	NO	Mon	Full
5464420	11	Dissolved Oxygen	36 / 3	5.9	16	11.9	0	NA / NA	7	NO	Mon	Full
14000348	6	pH	10 / 2	8.03	8.85	8.53	0	NA / NA	3	NO	Mon	Full
5464420	11	pH	49 / 3	7.5	8.8	8.3	0	NA / NA	9	NO	Mon	Full
99990021	14	pH	157 / 3	6.93	9.57	7.77	1	NA / NA	22	NO	Mon	Full
5464420	11	Sulfate	13 / 2	12.1	38.4	27.5	0	NA / NA	4	NO	Mon	Full
99990021	14	Sulfate	149 / 3	9	52	29	0	NA / NA	21	NO	Mon	Full
14000348	6	Temperature	10 / 2	6.53	29.14	20.85	0	NA / NA	3	NO	Mon	Full
5464420	11	Temperature	36 / 3	-0.1	27.9	12.1	0	NA / NA	7	NO	Mon	Full
99990021	14	Temperature	156 / 3	-0.44444	28.3889	12.615	0	NA / NA	21	NO	Mon	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
5464420	11	Ammonia	36 / 3	0.22	0.03	0.01	0 / 0	NO	Mon	Full
99990021	14	Ammonia	151 / 3	0.36	0.06	0.04	0 / 0	NO	Mon	Full
99990021	14	Copper	152 / 3	66.3	2.1	0.1	2 / 3	YES	Mon	Not
99990021	14	Lead	152 / 3	6.6	0.5	0.3	0 / 0	NO	Mon	Full
99990021	14	Zinc	152 / 3	67.6	6.5	5.7	0 / 0	NO	Mon	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)	WINOFI
Fish	Evaluated	Pass (1/1)	Full		Assessment was evaluated because the drainage area of
Overall	Evaluated	Fail	WINOFI	3bu	the sample site was greater than the calibrated range.

Class C - Binomial 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	9.8	36.6	24.9	25.6	0	NO	Mon	Full
99990021	14	Chloride	149 / 3	12	57	28	27	0	NO	Mon	Full
5464420	11	Fluoride	13 / 3	170	210	195	200	0	NO	Mon	Full
5464420	11	Inorganic nitrogen (nitrate and nitrite)	36 / 3	0.4	10.3	4.8	4.7	2	NO	Mon	Full
5464420	11	Nitrate	36 / 3	0.4	10.3	4.8	4.6	1	NO	Mon	Full
99990021	14	Nitrate	151 / 3	0.08	13.66	4.7	4.77	7	NO	Mon	Full
5464420	11	Nitrite	36 / 3	0.007	0.173	0.026	0.016	0	NO	Mon	Full
99990021	14	Nitrite	150 / 3	0.0025	0.15	0.02	0.0025	0	NO	Mon	Full
14000348	6	pH	10 / 2	8.03	8.85	8.53	8.61	0	NO	Mon	Full
5464420	11	pH	49 / 3	7.5	8.8	8.3	8.3	0	NO	Mon	Full
99990021	14	pH	157 / 3	6.93	9.57	7.77	7.84	1	NO	Mon	Full

Class C - Toxic Parameters:

Site ID	Data Source ID	Parameter Name	# Samples per Year (2020/ 2021/2022)	2020 Mean	2021 Mean	2022 Mean	# Non-Detects per Year (2020/ 2021/2022)	Support Level per Year (2020/ 2021/2022)	Assessment Type	Support Level
99990021	14	Lead	48/52/52	0.878	0.296	0.431	20/23/18	Full/Full/Full	Mon	Full

Class HH-FW - Toxic Parameters:

Site ID	Data Source ID	Parameter Name	# Samples per Year (2020/ 2021/2022)	2020 Mean	2021 Mean	2022 Mean	# Non-Detects per Year (2020/ 2021/2022)	Support Level per Year (2020/ 2021/2022)	Assessment Type	Support Level
99990021	14	Copper	48/52/52	3.463	1.391	1.473	37/43/17	Full/Full/Full	Mon	Full
99990021	14	Zinc	48/52/52	9.881	5.851	3.899	10/11/31	Full/Full/Full	Mon	Full

Monitoring and Methods

Assessment Key Dates

1/7/2020	Monitoring Start
12/27/2022	Monitoring End
9/23/2020	Biological Monitoring
1/24/2007	TMDL Completed
2/26/2010	TMDL Completed

Methods

200	Physical/Chemical Monitoring
315	Regional reference site approach
320	Benthic macroinvertebrate surveys
860	Other Agencies/Organizations provided monitoring data

Water Quality Assessments

Impaired Waters List

Cedar River IA 02-CED-456

Assessment Summary

Assessment Explanation

Assessment Key Dates

Methods