Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

South Raccoon River IA 04-RAC-1183

from confluence with Middle Raccoon R. (S9 T78N R29W Dallas Co.) to confluence with Brushy Cr. in S22 T79N R31W Guthrie Co.

Cycle
2020
Release Status
Final
Overall IR
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Unknown
Created
6/10/2020 9:38:10 AM
Updated
10/15/2020 11:40:37 AM
Use Support
Class A1
Recreation - Primary contact
WINOFI
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
High
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2008
Impairment Rationale
Geometric mean criterion exceeded
Data Source
TMDL monitoring: Iowa DNR
Class BWW1
Aquatic Life - Warm Water Type 1
Partially Supported
Support Level
Partially Supported
Impairment Code
5b - Biological impairment or pollutant-caused fish kill - unknown source. No administrative action.
Cause Magnitude
Moderate
Status
Continuing
Source
Agriculture
Source Confidence
Moderate
Cycle Added
2016
Impairment Rationale
Pollutant-caused fish kill
Data Source
Fish kill investigation: Iowa DNR
TMDL Priority
Tier IV
Class HH
Human Health -
Not Assessed
General Use
General Use water -
Not Assessed
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The Class A1 use remains assessed as "not supported" due to levels of indicator bacteria that violated state water quality criteria. The Class BWW1 use remains assessed as "partially supported" due to a fish kill investigation. All other designated uses were "not assessed".

Assessment Explanation

Sources of Data:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

Iowa DNR

6

BIO

See Below

860

South Raccoon River

Nations Bridge County Park - Stuart

Iowa DNR

6

WQ

CY 2005

11250001

South Raccoon River

Site 32 at Redfield

Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples / # Years

2005 Geometric Mean (4 samples)

Annual Geometric Mean Violation

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

11250001

6

4 / 1

6734

Yes

4

100%

NA

Evaluated

Not

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

181

7/25/12

330

47f

MS/WW

Hess

65

Good

51

Pass

Fish:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/Thermal

Riffle Stream?

FIBI score

FIBI Class

47f FIBI BIT

FIBI Pass/ Fail

181

7/25/12

330

47f

MS/WW

NA

53

Good

36

Pass

Overall:

Community

Assessment Type

Assessment Result

Support Level

Earned IR Category

Actual IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Pass (1/1)

Full

Fish

Evaluated

Pass (1/1)

Full

Overall

Evaluated

Pass

Full

1

1

Assessment is evaluated because it was based on an old single sample.


Class BWW1 – Fishkill Assessment:

The Class BWW1 aquatic life use assessment based on the 2014 fish kill placed this segment in Category 5b. The fish kill was caused by a “pollutant” or was suspected to be caused by a “pollutant”; therefore, the Class BWW1 use was considered impaired. Because the source of the pollutant was not identified and/or the enforcement actions taken against the responsible party have not been resolved, the Class BWW1 use was placed in Category 5b. Due to uncertainty regarding the recovery of the aquatic life following the fish kill, any existing fish kill 5b impairment will remain in Category 5b until more recent sampling has shown recovery of the aquatic community or the responsible party has paid restitution.

Details about the 2014 fish kill can be found here:https://programs.iowadnr.gov/fishkill/Events/874

Monitoring and Methods
Assessment Key Dates
7/25/2012
Biological Monitoring
5/26/2005
Non-fixed Monitoring Start Date
6/23/2005
Non-fixed Monitoring End Date
4/11/2014
Fish Kill
Methods
120
Surveys of fish and game biologists/other professionals
140
Incidence of spills and/or fish kills
150
Monitoring data more than 5 years old
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys
420
Indicator bacteria monitoring