2020 Final assessment for Volga River

Volga River IA 01-VOL-289

mouth (S36 T92N R4W Clayton Co.) to confluence with Cox Cr. in S21 T92N R5W Clayton 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: 4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
Trend: Unknown

Created: 8/25/2020 6:01:25 AM
Updated: 10/14/2020 10:54:03 AM

Assessment conducted in accordance with Iowa's 2020 IR methodology

Use Support

Class A1

Partially Supported

Bacteria: Indicator Bacteria- E. coli

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

Geometric mean criterion exceeded

Data Source

Ambient monitoring: Iowa DNR-rivers

Class BWW1

Fully Supported

Class HH

Fully Supported

General Use

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 primary contact recreation use remains assessed as "partially supported" due to levels of indicator bacteria (E. coli) that exceeded Iowa’s water quality standards. The Class BWW1 use was assessed as "fully supported" based on biological sampling data and on water quality monitoring data. The Class HH use was assessed as "fully supported" based on water quality monitoring data. Note: A TMDL for pathogen indicators in this segment of the Volga River was prepared by DNR and approved by EPA in 2006. Because the primary Section 303(d) impairment identified for the 2006 IR cycle (indicator bacteria) was addressed by the TMDL, the Class A use was moved from IR Category 5a from the 2004 IR cycle to IR Category 4a (impaired; TMDL approved) for the 2006 cycle.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2016-2018	10220002	Volga River near Elkport
Iowa DNR	6	BIO	See Below	283	Volga River	Elkport

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
10220002	6	19 / 3	586.72	270.94	916.03	Yes	12	63%	Yes	Monitored	Partial

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
10220002	6	36 / 3	8.4	8.1	8.2	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
10220002	6	Ammonia	36 / 3	0.08	0.03	0.02	0 / 0	0% / 0%	No	Monitored	Full
10220002	6	Chloride	36 / 3	18	13	14	0 / 0	0% / 0%	No	Monitored	Full
10220002	6	Dissolved Oxygen	36 / 3	13.8	10.5	10	NA / 0	NA / 0%	No	Monitored	Full
10220002	6	pH	36 / 3	8.4	8.1	8.2	0 / NA	0% / NA	No	Monitored	Full
10220002	6	Sulfate	36 / 3	23	17	18	0 / NA	0% / NA	No	Monitored	Full
10220002	6	Temperature	36 / 3	23.2	11.4	12.3	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
10220002	6	Aluminum	9 / 2	7.4	1.61	0.71	0 / 0	0% / 0%	No	Evaluated	Full
10220002	6	Arsenic	9 / 2	1	0.585	0.63	0 / 0	0% / 0%	No	Evaluated	Full
10220002	6	Cadmium	9 / 2	0.025	0.025	0.025	0 / 0	0% / 0%	No	Evaluated	Full
10220002	6	Chromium	9 / 2	1.5	0.894	0.98	0 / 0	0% / 0%	No	Evaluated	Full
10220002	6	Copper	9 / 2	2.3	0.74	0.55	0 / 0	0% / 0%	No	Evaluated	Full
10220002	6	Lead	9 / 2	0.86	0.146	0.05	0 / 0	0% / 0%	No	Evaluated	Full
10220002	6	Nickel	9 / 2	2.1	1.714	1.9	0 / 0	0% / 0%	No	Evaluated	Full
10220002	6	Selenium	9 / 2	0.88	0.67	0.79	0 / 0	0% / 0%	No	Evaluated	Full
10220002	6	Zinc	9 / 2	1.9	1.093	1.1	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	52b BMIBI BIT	BMIBI Pass/ Fail
283	9/18/15	403	52b	MS/WW	Float ArtSub	46	Fair	61	Fail
283	8/12/15	403	52b	MS/WW	Float ArtSub	68	Good	61	Pass
283	10/7/14	403	52b	MS/WW	Float ArtSub	72	Good	61	Pass

Overall Assessment:

Community	Assessment Type	Assessment Result	Support Level	Earned IR Category	Actual IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Pass (2/3)	Full	1	1	Assessment is monitored because all samples used to complete assessment were collected in the last five years.

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
10220002	6	Cadmium	9 / 2	0.025	0.025	0.025	9	No	All Non-Detect	Full
10220002	6	Chromium	9 / 2	1.5	0.894	0.98	1	No	Evaluated	Full
10220002	6	Copper	9 / 2	2.3	0.74	0.55	0	No	Evaluated	Full
10220002	6	Nickel	9 / 2	2.1	1.714	1.9	1	No	Evaluated	Full
10220002	6	Selenium	9 / 2	0.88	0.67	0.79	2	No	Evaluated	Full
10220002	6	Zinc	9 / 2	1.9	1.093	1.1	0	No	Evaluated	Full

Monitoring and Methods

Assessment Key Dates

1/11/2016	Fixed Monitoring Start Date
12/5/2018	Fixed Monitoring End Date
10/7/2014	Biological Monitoring
8/12/2015	Biological Monitoring
9/18/2015	Biological Monitoring
7/1/2006	TMDL Completed

Methods

230	Fixed station physical/chemical (conventional plus toxic pollutants)
240	Non-fixed station physical/chemical (conventional + toxicants)
315	Regional reference site approach
320	Benthic macroinvertebrate surveys
330	Fish surveys
420	Indicator bacteria monitoring

Water Quality Assessments

Impaired Waters List

Volga River IA 01-VOL-289

Assessment Summary

Assessment Explanation

Assessment Key Dates

Methods