North Branch Volga River IA 01-VOL-330

mouth (S33 T93N R9W Fayette Co.) to confluence with unnamed tributary in S8 T93N R9W 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 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.

Open Segment Map
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Cycle: 2022
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 12/16/2021 8:46:48 AM
Updated: 1/4/2022 8:43:10 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not Supported

Impairment Code

5p - Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2014

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Watershed project monitoring

TMDL Priority

Tier III

Class BWW2

Aquatic Life - Warm Water Type 2

Fully Supported

Class HH

Human Health -

Not Supported

Fish Consumption Advisory: Mercury

Support Level

Not Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2014

Impairment Rationale

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

Data Source

Fish contaminant monitoring: Iowa DNR

TMDL Priority

Tier IV

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use was assessed as “not supported” due to violations of Iowa water quality criteria for indicator bacteria (E. coli). The Class BWW2 use was assessed as "fully supported" based on biological sampling data and water quality monitoring data. The Class HH use was assessed as “not supported" due to existence of a one meal/week mercury consumption advisory for smallmouth bass in this segment.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2012-2014	15330014	Volga River, North Branch at Hwy 93	VRN-10
Iowa DNR	6	BIO	See Below	264	North Branch Volga River	Randalia – NV001

Presumptive Class A1 – Indicator Bacteria: 2012-2014

Site ID	Data Source ID	# Samples / # Years	2012 Geometric Mean	2013 Geometric Mean	2014 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
15330014	6	24 / 3	723	964	345	Yes	21	88%	Yes	Evaluated	Not

Presumptive Class A1 - pH: 2012-2014

Site ID	Data Source ID	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
15330014	6	24 / 3	8.9	8.11	8	0	0%	No	Evaluated	Full

Class BWW1 - Conventional Parameters: 2012-2014

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
15330014	6	Ammonia	15 / 2	0.25	0.08	0.06	0 / 0	0% / 0%	No	Evaluated	Full
15330014	6	Chloride	19 / 3	48	32	30	0 / 0	0% / 0%	No	Evaluated	Full
15330014	6	Dissolved oxygen	24 / 3	12	8	8	NA / 0	NA / 0%	No	Evaluated	Full
15330014	6	pH	24 / 3	8.9	8.11	8	0 / NA	0% / NA	No	Evaluated	Full
15330014	6	Temperature	24 / 3	24.5	13.8	13.4	0 / 0	0% / 0%	No	Evaluated	Full

Class BWW1 - Biological Sampling:

Fish:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47c FIBI BIT	FIBI Pass/Fail
264	8/19/19	24.5	47c	MS	No	71	Excellent	44	Pass
264	8/23/18	24.5	47c	MS	No	72	Excellent	44	Pass
264	8/25/17	24.5	47c	MS	No	64	Good	44	Pass
264	8/26/16	24.5	47c	MS	No	60	Good	44	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Fish	Monitored	Pass (4/4)	Full		Assessment was monitored because the assessment used multiple
Overall	Monitored	Pass	Full	1	samples collected in a recent five year period to complete the assessment.

Class HH - Fish Tissue Sampling:

Support Level

Not

A one meal/week mercury consumption advisory for smallmouth bass exists on this segment. Based on IR Methodology, the Class HH (fish consumption) use was assessed as “not supported.”

Monitoring and Methods

Assessment Key Dates

4/4/2012

Fixed Monitoring Start Date

11/5/2014

Fixed Monitoring End Date

8/19/2019

Biological Monitoring

8/26/2016

Biological Monitoring

8/25/2017

Biological Monitoring

8/23/2018

Biological Monitoring

Methods

150

Monitoring data more than 5 years old

220

Non-fixed station physical/chemical monitoring (conventional pollutant only)

260

Fish tissue analysis

315

Regional reference site approach

330

Fish surveys

380

Quantitative physical habitat assessment

420

Indicator bacteria monitoring