Yellow River IA 01-YEL-2060

from confluence with unnamed tributary in SE 1/4 S8 T96N R7W to headwaters (T96N R8W Sec3 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 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
View assessment methodology in new window

Cycle: 2020
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 8/7/2020 1:46:19 PM
Updated: 10/12/2020 1:58:02 PM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Partially Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Partially Supported

Impairment Code

5p - Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.

Cause Magnitude

High

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2014

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Special project/study: Iowa DNR

TMDL Priority

Tier III

Support Level

Partially 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

2016

Impairment Rationale

Significantly > 10% of samples fail to meet criterion

Data Source

Special project/study: Iowa DNR

TMDL Priority

Tier IV

Class BWW1

Presumptive Use

Aquatic Life - Warm Water Type 1

Partially Supported

Support Level

Partially 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

Special project/study: Iowa DNR

TMDL Priority

Tier III

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use remains assessed as "not supported” based on violations of water quality criteria for indicator bacteria (E. coli) and "partially supported" based on violations of water quality criteria for pH. The presumptive Class BWW1 use remains assessed as “partially supported” due to violations of the Class BWW1 water quality criterion for pH.

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	11960008	Yellow River near Castalia	Site YeRi5
Iowa DNR	6	WQ	CY 2011 & CY 2014	15960042	Yellow River at Sand Rd	Site 9

Presumptive Class A1 - Indicator Bacteria: CY 2014

Site ID	Data Source ID	# Samples / # Years	2014 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
11960008	6	20 / 1	736	Yes	15	75%	Yes	Monitored	Partial
15960042	6	19 / 1	1092	Yes	17	89%	Yes	Monitored	Not

Presumptive Class A1 - pH: CY 2011

Site ID	Data Source ID	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
11960008	6	13 / 1	9.8	8.6	8.6	4	31%	Yes	Evaluated	Partial
15960042	6	13 / 1	9.8	8.6	8.6	3	23%	Yes	Evaluated	Partial

Presumptive Class BWW1 - Conventional Parameters: CY 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
11960008	6	Ammonia	7 / 1	0.05	0.05	0.05	0 / 0	0% / 0%	No	Evaluated	Full
11960008	6	Dissolved Oxygen	13 / 1	17.3	10.2	9.6	0 / 0	NA / 0%	No	Evaluated	Full
11960008	6	pH	13 / 1	9.8	8.6	8.6	4 / NA	31% / NA	Yes	Evaluated	Partial
11960008	6	Temperature	13 / 1	17.6	12.2	12.5	0 / 0	0% / 0%	No	Evaluated	Full
15960042	6	Ammonia	7 / 1	0.09	0.06	0.05	0 / 0	0% / 0%	No	Evaluated	Full
15960042	6	Dissolved Oxygen	13 / 1	16.2	9.5	7.9	0 / 0	NA / 0%	No	Evaluated	Full
15960042	6	pH	13 / 1	9.8	8.6	8.6	3 / NA	23% / NA	Yes	Evaluated	Partial
15960042	6	Temperature	13 / 1	19.1	13.7	13.4	0 / 0	0% / 0%	No	Evaluated	Full

Monitoring and Methods

Assessment Key Dates

4/22/2014

Non-fixed Monitoring Start Date

10/8/2014

Non-fixed Monitoring End Date

4/18/2011

Non-fixed Monitoring Start Date

10/25/2011

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