South Fork Chariton River IA 05-CHA-1327

mouth (at Rathbun Lake) to confluence with Ninemile Cr. in S4 T69N R22W Wayne 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: Stable
Created: 9/30/2020 7:44:08 AM
Updated: 10/12/2020 10:40:40 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

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2008

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Ambient monitoring: Corps of Engineers/Iowa DNR/ISU

TMDL Priority

Tier III

Class BWW2

Aquatic Life - Warm Water Type 2

Partially Supported

Biological: low fish IBI

Support Level

Partially Supported

Impairment Code

5b-t - Biological - tentative

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2006

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR Fisheries

TMDL Priority

Tier IV

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use was assessed as "not supported" due to levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class BWW2 use was assessed as “not supported” based on biological sampling data.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
USACE	12	WQ	CY 2010-2014	15930001	South Fork Chariton River (Site RA-12)
Iowa DNR	6	BIO	See Below	SF5	South Fork Chariton River
Iowa DNR	6	BIO	See Below	SF7	South Fork Chariton River
Iowa DNR	6	BIO	See Below	SF8	South Fork Chariton River
Iowa DNR	6	BIO	See Below	SF9	South Fork Chariton River

Presumptive Class A1 - Indicator Bacteria: 2010-2012

Site ID	Data Source ID	# Samples / # Years	2010 Geometric Mean	2011 Geometric Mean	2012 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
15930001	6	19 / 3	794	1368	576	Yes	13	68%	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
15930001	6	59 / 3	8.4	7.5	7.6	0	0%	No	Evaluated	Full

Class BWW2 - 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
15930001	6	Ammonia	30 / 3	0.98	0.1	0.05	0 / 0	0% / 0%	No	Evaluated	Full
15930001	6	Chloride	40 / 3	17	7.9	7.8	0 / 0	0% / 0%	No	Evaluated	Full
15930001	6	Dissolved oxygen	59 / 3	13.1	8.5	7.9	NA / 0	NA / 0%	No	Evaluated	Full
15930001	6	pH	59 / 3	8.4	7.5	7.6	0 / NA	0% / NA	No	Evaluated	Full
15930001	6	Temperature	59 / 3	28.6	17.5	18.4	0 / 0	0% / 0%	No	Evaluated	Full

Class BWW2 - Biological Sampling:

Fish:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/Thermal	Riffle Stream?	FIBI score	FIBI Class	40a FIBI BIT	FIBI Pass/ Fail
SF8	7/25/02	NA	40a	MO/WW	NA	21	Poor	33	Fail
SF7	7/31/02	NA	40a	MO/WW	NA	24	Poor	33	Fail
SF5	8/26/02	NA	40a	MO/WW	NA	22	Poor	33	Fail
SF9	8/26/02	NA	40a	MO/WW	NA	28	Poor	33	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	Earned IR Category	Actual IR Category	Reason
Fish	Evaluated	Fail (0/4)	Not	3bc	5bt	Assessment is evaluated because it was based on samples not collected in the last five years.

Monitoring and Methods

Assessment Key Dates

3/14/2012

Fixed Monitoring Start Date

10/21/2014

Fixed Monitoring End Date

8/26/2002

Biological Monitoring

7/31/2002

Biological Monitoring

7/25/2002

Biological Monitoring

3/6/2010

Fixed Monitoring Start Date

10/22/2012

Fixed Monitoring End Date

Methods

150

Monitoring data more than 5 years old

220

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

315

Regional reference site approach

330

Fish surveys

420

Indicator bacteria monitoring