Unnamed Tributary to Unnamed Tributary to Yellow River IA 01-YEL-6575

from mouth (T96N R7W Sec15) to headwaters (T96N R7W Sec21) Winneshiek 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: 1/11/2022 7:11:18 AM
Updated: 1/11/2022 7:14:28 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

N/A

Cycle Added

2014

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Watershed project monitoring

TMDL Priority

Tier III

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

N/A

Cycle Added

2014

Impairment Rationale

Significantly > 10% of samples fail to meet criterion

Data Source

Watershed project monitoring

TMDL Priority

Tier III

Class BWW1

Presumptive Use

Aquatic Life - Warm Water Type 1

Not Supported

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

N/A

Cycle Added

2014

Impairment Rationale

Significantly > 10% of samples fail to meet criterion

Data Source

Watershed project monitoring

TMDL Priority

Tier IV

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 (E. coli) and pH that exceeded state water quality criteria. The presumptive Class BWW1 use remains assessed as “not supported” due to levels of pH that exceeded state water quality criteria.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2011; CY 2014	15960038	Unnamed Creek at 130 Ave	Site 6

Presumptive Class A1 - Indicator Bacteria: 2014

Site ID	Data Source ID	# Samples / # Years	2014 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
15960038	6	20 / 1	293	Yes	14	70%	Yes	Evaluated	Not

Presumptive Class A1 - pH: 2011

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
15960038	6	pH	14 / 1	10.1	8.7	8.6	5 / NA	36% / NA	Yes	Evaluated	Not

Presumptive Class BWW1 - Conventional Parameters: 2011

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
15960038	6	Ammonia	8 / 1	0.05	0.05	0.05	0 / 0	0% / 0%	No	Evaluated	Full
15960038	6	Dissolved oxygen	14 / 1	15.2	9.4	8.6	NA / 0	NA / 0%	No	Evaluated	Full
15960038	6	pH	14 / 1	10.1	8.7	8.6	5 / NA	36% / NA	Yes	Evaluated	Not
15960038	6	Temperature	14 / 1	16.3	12.1	12.2	0 / 0	0% / 0%	No	Evaluated	Full

Monitoring and Methods

Assessment Key Dates

4/18/2011

Non-fixed Monitoring Start Date

10/25/2011

Non-fixed Monitoring End Date

4/22/2014

Non-fixed Monitoring Start Date

10/8/2014

Non-fixed Monitoring End Date

Methods

150

Monitoring data more than 5 years old

220

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

420

Indicator bacteria monitoring