Iowa DNR
Iowa DNR

ADBNet

Water Quality Assessments
Impaired Waters List

Volga River IA 01-VOL-290

from confluence with Cox Cr. (S21 T92N R5W Clayton Co.) to bridge crossing in Volga (north line S10 T92N R6W Clayton Co.).

Overall IR
4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
Trend
Unknown
Created
11/1/2023 8:14:04 AM by
Updated
12/12/2023 2:24:00 PM by
Use Support
Class A1
Recreation - Primary contact
Not Supported
Support Level
Not Supported
Impairment Code
4a - Pollutant-caused impairment. TMDL has been completed.
Cause Magnitude
Slight
303(d) Listing Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2002
Impairment Rationale
Geometric mean criterion exceeded
Data Source
TMDL monitoring: Iowa DNR
Class BWW1
Aquatic Life - Warm Water Type 1
Fully Supported
Class HH
Human Health -
Not Assessed
No delistings for this assessment cycle.
Documentation
Assessment Summary

The Class A1 use remains assessed as "not supported" based on levels of indicator bacteria (E. coli) that violated state water quality standards. The Class BWW1 use was assessed as "fully supported" based on biological sampling data. All other designated uses were “not assessed." Note: A TMDL for pathogen indicators in this segment of the Volga River was prepared by DNR and approved by EPA in 2006. This waterbody remains in IR Category 4a.

Assessment Explanation

Data Sources:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

Iowa DNR

6

WQ

CY 2001

11220004

Volga River E of Volga, Osborne Park (34)

Iowa DNR

6

WQ

CY 2001

11220007

Volga River at Volga (35)

Iowa DNR

6

BIO

See Below

1309

Volga River

Volga (REMAP #269)


Class A1 - Indicator Bacteria: Historical

Site ID

Data Source ID

# Samples / # Years

2001 Geometric Mean

Annual Geometric Mean Violation

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

11220004

6

9 / 1

245

Yes

4

44%

NA

Evaluated

Not

11220007

6

9 / 1

276

Yes

4

44%

NA

Evaluated

Not


Class BWW1 - Biological Sampling:


Benthic Macroinvertebrates:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

BM Sample Gear

BMIBI score

BMIBI Class

52b BMIBI BIT

BMIBI Pass/Fail

1309

7/28/21

262.0

52b

MS

Hess

86

Excellent

61

Pass


Fish:

Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage

Riffle Stream?

FIBI score

FIBI Class

52b FIBI BIT

FIBI Pass/Fail

1309

7/28/21

262.0

52b

MS

NA

84

Excellent

52

Pass


Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Pass (1/1)

Full

Fish

Evaluated

Pass (1/1)

Full

1

Assessment was evaluated because it was based on a single sample.

Overall

Evaluated

Pass

Full


Class HH - No Data



Monitoring and Methods
Assessment Key Dates
3/27/2001
Monitoring Start
11/13/2001
Monitoring End
11/9/2006
TMDL Completed
7/28/2021
Biological Monitoring
Methods
150
Monitoring data more than 5 years old
200
Physical/Chemical Monitoring
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys
420
Indicator bacteria monitoring