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 2020 - 2022
Stream/River Water Quality Data	CY 2020 - 2022
Lake Water Quality Data	CY 2018 - 2022
Biological Sampling Data	CY 2018 - 2022*
Fish Kill Data	CY 2018 - 2022
Fish Tissue Sampling Data	CY 2018 - 2022
Continuous Dissolved Oxygen Sampling Data	CY 2018 - 2022
*Biological sites sampled in both 2017 and 2021 were also assessed.

Open Segment Map
View assessment methodology in new window

Cycle: 2024
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Stable
Created: 11/1/2023 8:13:14 AM
Updated: 1/11/2024 6:16:26 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

Not Supported

Biological: low fish IBI

Support Level

Not 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

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use remains assessed as "not supported" due to levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class BWW2 use remains 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 2012-2014, CY 2021	15930001	South Fork Chariton River at CR S50/200th St. (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: 2012-2014

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

Site ID	Data Source ID	# Samples / # Years	Minimum Value	Maximum Value	Mean Value	# Violations	Violations needed for impairment	Violates Significantly >10% Rule?	Assessment Type	Support Level
15930001	12	6 / 1	7.41	8.01	7.72	0	3	NO	Evaluated	Full

Class BWW2 - Binomial Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Minimum Value	Maximum Value	Mean Value	# Violations	# Acute / Chronic Violations	Violations needed for impairment	Violates Significantly >10% Rule?	Assessment Type	Support Level
15930001	12	Dissolved Oxygen	6 / 1	5.8	9	7.7	0	NA / NA	3	NO	Evaluated	Full
15930001	12	pH	6 / 1	7.41	8.01	7.72	0	NA / NA	3	NO	Evaluated	Full
15930001	12	Temperature	6 / 1	20.62	26.64	23.95	0	NA / NA	3	NO	Evaluated	Full

Class BWW2 - Toxic Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Acute / Chronic Violations	>1 Acute / Chronic Violation	Assessment Type	Support Level
15930001	12	Ammonia	6 / 1	0.17	0.09	0.08	0 / 0	NO	Evaluated	Full

Class BWW2 - Biological Sampling:

Fish:

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

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Fish	Evaluated	Fail (0-4)	Not		Assessment was evaluated because it was based on samples
Overall	Evaluated	Fail	Not	5bt	collected in a single year and not collected in the last five years.

Monitoring and Methods

Assessment Key Dates

3/14/2012

Monitoring Start

10/21/2014

Monitoring End

8/26/2002

Biological Monitoring

7/31/2002

Biological Monitoring

7/25/2002

Biological Monitoring

4/27/2021

Monitoring Start

9/29/2021

Monitoring End

Methods

150

Monitoring data more than 5 years old

200

Physical/Chemical Monitoring

315

Regional reference site approach

330

Fish surveys

420

Indicator bacteria monitoring