Cedar River IA 02-CED-451

from Rock Run Cr. (S28 T80NR3W Cedar Co ) to Hwy 30 bridge at Cedar Rapids in S9 T82N R6W Linn Co.

Assessment Cycle

2020

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 2016 - 2018
Stream/River Water Quality Data	CY 2016 - 2018
Lake Water Quality Data	CY 2014 - 2018
Biological Sampling Data	CY 2014 - 2018*
Fish Kill Data	CY 2014 - 2018
Fish Tissue Sampling Data	CY 2014 - 2018
Continuous Dissolved Oxygen Sampling Data	CY 2014 - 2018
*Biological sites sampled in both 2013 and 2017 were also assessed.

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

Created: 8/28/2020 7:37:27 AM
Updated: 10/16/2020 7:29:03 AM

Assessment conducted in accordance with Iowa's 2020 IR methodology

Use Support

Class A1

Recreation

Primary contact

Partially Supported

Impairments

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

2002

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Ambient monitoring: Iowa DNR-rivers

Class BWW1

Aquatic Life

Warm Water Type 1

Not Supported

Impairments

Support Level

Not Supported

Impairment Code

5b - Biological impairment or pollutant-caused fish kill - unknown source. No administrative action.

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2004

Impairment Rationale

Loss of >50% of native mussel species

Data Source

Special project/study

TMDL Priority

Tier IV

Class HH

Human Health

Fully Supported

General Use

General Use water

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use was assessed as "partially supported" due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class BWW1 use remains assessed as "not supported" based on results of a 1998-99 statewide survey of freshwater mussels. The Class HH use was assessed as “fully supported” based on ambient water quality monitoring 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 bacteria 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 2016-2018	10570001	Cedar River Downstream of Cedar Rapids (DS1)
Iowa DNR	6	BIO	See Below	952	Cedar River	Cedar Rapids -DS1

Class A1 - Indicator Bacteria:

Site ID	Data Source ID	# Samples / # Years	2016 Geometric Mean	2017 Geometric Mean	2018 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
10570001	6	24 / 3	233.44	97.95	244.65	Yes	11	46%	Yes	Monitored	Partial

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
10570001	6	36 / 3	9.1	8.3	8.3	1	3%	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
10570001	6	Ammonia	36 / 3	0.79	0.1	0.02	0 / 0	0% / 0%	No	Monitored	Full
10570001	6	Chloride	36 / 3	43	24	24	0 / 0	0% / 0%	No	Monitored	Full
10570001	6	Dissolved oxygen	36 / 3	17.2	11.6	11.7	NA / 0	NA / 0%	No	Monitored	Full
10570001	6	pH	36 / 3	9.1	8.3	8.3	1 / NA	3% / NA	No	Monitored	Full
10570001	6	Sulfate	36 / 3	49	26	27	0 / NA	0% / NA	No	Monitored	Full
10570001	6	Temperature	36 / 3	27.8	12.6	12.4	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
10570001	6	Aluminum	9 / 2	1.7	0.728	0.84	0 / 0	0% / 0%	No	Evaluated	Full
10570001	6	Arsenic	9 / 2	2.3	1.7	1.6	0 / 0	0% / 0%	No	Evaluated	Full
10570001	6	Cadmium	9 / 2	0.025	0.025	0.025	0 / 0	0% / 0%	No	Evaluated	Full
10570001	6	Chromium	9 / 2	1.1	0.71	0.72	0 / 0	0% / 0%	No	Evaluated	Full
10570001	6	Copper	9 / 2	3.5	1.21	1	0 / 0	0% / 0%	No	Evaluated	Full
10570001	6	Lead	9 / 2	0.14	0.067	0.05	0 / 0	0% / 0%	No	Evaluated	Full
10570001	6	Nickel	9 / 2	3.1	2.2	2.2	0 / 0	0% / 0%	No	Evaluated	Full
10570001	6	Selenium	9 / 2	1.8	1.26	1.3	0 / 0	0% / 0%	No	Evaluated	Full
10570001	6	Zinc	9 / 2	3.6	1.62	1.2	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	47f BMIBI BIT	BMIBI Pass/ Fail
952	8/24/15	6955	47f	MS/WW	Float ArtSub	56	Good	51	Pass
952	10/11/14	6955	47f	MS/WW	Float ArtSub	52	Fair	51	Pass

Overall Assessment:

Community	Assessment Type	Assessment Result	Support Level	Earned IR Category	Actual IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Pass (2/2)	Full	1	1	Assessment is evaluated because the drainage area of the sample site is larger than calibrated range.

Class BWW1 – Freshwater Mussel Sampling:

Freshwater Mussel Survey	Avg. # Freshwater Mussel Species	Avg. # Freshwater Mussel Species Increase/Decrease	Avg % Freshwater Mussel Species Increase/Decrease	Assessment Type	Support Level	IR Category
1984-85 (Frest 1987) 5 sites	5.6
1998-99 (Arbuckle et al. 2000) 5 sites	0.4	-5	-92%	Evaluated	Not	5b
As presented by Arbuckle et al. (2000), the potential causes of declines in species richness of Iowa's freshwater mussels include siltation, destabilization of stream substrate, stream flow instability, and high instream levels of nutrients (phosphorus and nitrogen). Their study also suggested the importance of stream shading provided by riparian vegetation to mussel species richness.

Class HH-F - 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
10570001	6	Cadmium	9 / 2	0.025	0.025	0.025	9	No	All Non-Detect	Full
10570001	6	Chromium	9 / 2	1.1	0.71	0.72	0	No	Evaluated	Full
10570001	6	Copper	9 / 2	3.5	1.21	1	0	No	Evaluated	Full
10570001	6	Nickel	9 / 2	3.1	2.2	2.2	0	No	Evaluated	Full
10570001	6	Selenium	9 / 2	1.8	1.26	1.3	0	No	Evaluated	Full
10570001	6	Zinc	9 / 2	3.6	1.62	1.2	0	No	Evaluated	Full

Monitoring and Methods

Assessment Key Dates

9/30/1999

Biological Monitoring

1/5/2016

Fixed Monitoring Start Date

12/6/2018

Fixed Monitoring End Date

10/11/2014

Biological Monitoring

8/24/2015

Biological Monitoring

2/1/2010

TMDL Completed

Methods

120

Surveys of fish and game biologists/other professionals

230

Fixed station physical/chemical (conventional plus toxic pollutants)

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

420

Indicator bacteria monitoring