Winnebago River IA 02-WIN-826

mouth (Floyd Co.) to confluence with Calmus Cr. at Mason City in S34 T97N R20W Cerro Gordo 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: 12/14/2021 11:04:37 AM
Updated: 1/4/2022 1:14:07 PM

Use Support

Class A1

Recreation - Primary contact

Not Supported

Bacteria: Indicator Bacteria- E. coli

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

2008

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Ambient monitoring: Iowa DNR-rivers

TMDL Priority

Tier III

Class BWW1

Aquatic Life - Warm Water Type 1

Fully Supported

Class HH

Human Health -

Fully Supported

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use was assessed as "not supported" due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class BWW1 use was assessed as "fully supported” based on biological sampling data and water quality monitoring data. The Class HH use was assessed as "fully supported" based on fish tissue sampling data.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	BIO	See Below	1035	Winnebago River	Winnebago near Fossil Rock Park
Iowa DNR	6	WQ	CY 2012-2014	10170003	Winnebago River	Downstream of Mason City (DS1)
Iowa DNR	6	FT	See Below	135	Winnebago River	E of Mason City

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
10170003	6	22 / 3	387	222	371	Yes	13	59%	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
10170003	6	33 / 3	8.5	8.1	8.2	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
10170003	6	Ammonia	33 / 3	0.49	0.11	0.05	0 / 0	0% / 0%	No	Evaluated	Full
10170003	6	Chloride	33 / 3	150	50	41	0 / 0	0% / 0%	No	Evaluated	Full
10170003	6	Dissolved oxygen	33 / 3	15.4	10.8	11.1	NA / 0	NA / 0%	No	Evaluated	Full
10170003	6	pH	33 / 3	8.5	8.1	8.2	0 / NA	0% / NA	No	Evaluated	Full
10170003	6	Sulfate	33 / 3	110	70	74	0 / NA	0% / NA	No	Evaluated	Full
10170003	6	Temperature	33 / 3	26.8	11.5	14.7	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
1035	8/1/19	695	47c	MS	Undetermined	59	Good	44	Pass
1035	8/13/18	695	47c	MS	Undetermined	54	Good	44	Pass
1035	7/12/17	695	47c	MS	Undetermined	44	Fair	44	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Fish	Evaluated	Pass (3/3)	Full		Assessment was evaluated because the drainage area of the site used for
Overall	Evaluated	Pass	Full	1	the assessment was greater than the calibrated range.

Class HH - Fish Tissue Sampling:

Site ID	Biopart	Year	Species	# in sample / # of samples	Avg Length (cm)	(Avg) Hg (ppm)	Chlordane (ppm)	Sum PCBs (ppm)
135	fillet	2012	common carp	5	51.3	0.122	0.03	0.09
135	tissue plug	2015	walleye	5	41.9	0.092
Support Level	Full

Monitoring and Methods

Assessment Key Dates

8/28/2012

Fish Tissue Monitoring

1/3/2012

Fixed Monitoring Start Date

9/8/2014

Fixed Monitoring End Date

8/21/2015

Fish Tissue Monitoring

7/12/2017

Biological Monitoring

8/13/2018

Biological Monitoring

8/1/2019

Biological Monitoring

Methods

150

Monitoring data more than 5 years old

210

Fixed station physical/chemical monitoring (conventional pollutants only)

260

Fish tissue analysis

315

Regional reference site approach

330

Fish surveys

420

Indicator bacteria monitoring