Volga River IA 01-VOL-294

confluence with Brush Cr. (S26 TT93N R7W Fayette Co.) to east corporate limit of Fayette (NE 1/4 S28 T93N R8W Fayette Co.)

Open Data Collection Period Modal

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.

Open Segment Map
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Cycle: 2020
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 8/7/2020 8:14:56 AM
Updated: 10/14/2020 10:55:10 AM

Use Support

Class A1

Recreation - Primary contact

Not Assessed

Class BWW1

Aquatic Life - Warm Water Type 1

Not Assessed

Class HH

Human Health -

Partially Supported

Fish Consumption Advisory: Mercury

Support Level

Partially Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2008

Impairment Rationale

Fish consumption advisory in effect: no more than 1 meal/week

Data Source

Fish contaminant monitoring: Iowa DNR

TMDL Priority

Tier IV

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class HH use remains assessed as "partially supported" based on fish tissue sampling data and the existence of a one meal per week consumption advisory for smallmouth bass in this segment. All other designated uses were "not assessed".

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	FT	See Below	203	Volga River	Near Volga Recreation Area

Class A1 – No Data:

Class BWW1 – No Data:

Class HH – Fish Tissue Sampling:

Site ID	Date	Species Name	Biopart	# in sample	Hg result	Hg violation (>0.3)?	Assessment Type	Support Level
203	8/1/2008	smallmouth bass	fillet	3	0.326	Yes	Evaluated	Not
203	8/28/2012	smallmouth bass	plug	5	0.214	No	Evaluated	Full
203	8/29/2014	smallmouth bass	plug	3	0.287	No	Monitored	Full
The average level of mercury in tissue plugs from three smallmouth bass was 0.287 ppm in 2014. This level of mercury is sufficiently close to the advisory threshold of 0.3 ppm to justify continuing the existing consumption advisory and mercury impairment. A one meal/week consumption advisory for mercury exists on this segment of the Volga River – see Iowa Consumption Advisories

Monitoring and Methods

Assessment Key Dates

8/1/2008

Fish Tissue Monitoring

8/28/2012

Fish Tissue Monitoring

8/29/2014

Fish Tissue Monitoring

Methods

150

Monitoring data more than 5 years old

260

Fish tissue analysis