East Branch Blue Creek IA 02-CED-1880

from confluence with Blue Creek (T85N R8W Sec7 Linn Co.) to headwaters in NE1/4 S33 T87N 8W Buchanan 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
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Cycle: 2024
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 11/1/2023 8:13:14 AM
Updated: 1/16/2024 1:25:52 PM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

WINOFI

Bacteria: Indicator Bacteria- E. coli

Support Level

Further Investigation Needed

Impairment Code

3b - Use potentially impaired based on an evaluated assessment.

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2022

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Watershed project monitoring

Class BWW1

Presumptive Use

Aquatic Life - Warm Water Type 1

Not Supported

Fish Kill: Caused By Fertilizer Spill

Support Level

Not Supported

Impairment Code

5b - Biological impairment or pollutant-caused fish kill - unknown source. No administrative action.

Cause Magnitude

Moderate

Status

Continuing

Source

Agriculture: Agricultural chemical dealer

Source Confidence

N/A

Cycle Added

2006

Impairment Rationale

Pollutant-caused fish kill

Data Source

Fish kill investigation: Iowa DNR

TMDL Priority

Tier IV

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use was assessed as “WINOFI” based on levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The presumptive Class BWW1 use was assessed as "not supported" due to a fish kill investigation.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
CRWQ	23	WQ	CY 2020-2022	99990039	East Branch Blue Creek

Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples per Year (2020/ 2021/2022)

2020 Geometric Mean

2021 Geometric Mean

2022 Geometric Mean

Violates Annual Geometric Mean?

# 2020 SSM violations / SSM Violations needed for impairment

# 2021 SSM violations / SSM Violations needed for impairment

# 2022 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

99990039

5/5/5

615

520

274

YES

4 / NA

5 / NA

4 / NA

YES

Evaluated

Not

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
99990039	23	13 / 3	6.76	8.41	7.95	0	4	NO	Mon	Full

Class BWW1 - 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
99990039	23	Chloride	15 / 3	18	24.7	21.6	NA	0 / 0	4	NO	Mon	Full
99990039	23	Dissolved Oxygen	14 / 3	6.9	13.6	9.1	0	NA / NA	4	NO	Mon	Full
99990039	23	pH	13 / 3	6.76	8.41	7.95	0	NA / NA	4	NO	Mon	Full
99990039	23	Sulfate	15 / 3	16.7	24.7	20.5	0	NA / NA	4	NO	Mon	Full
99990039	23	Temperature	15 / 3	7.4	26.7	17.7	0	NA / NA	4	NO	Mon	Full

Presumptive Class BWW1 - Fish kill Assessment:

The presumptive Class BWW1 aquatic life use assessment based on the 2005 fish kill placed this segment in Category 5b. The fish kill was caused by a “pollutant” or was suspected to be caused by a “pollutant”; therefore, the presumptive Class BWW1 use was considered impaired. Because the source of the pollutant was not identified and/or the enforcement actions taken against the responsible party have not been resolved, the presumptive Class BWW1 use was placed in Category 5b. Due to uncertainty regarding the recovery of the aquatic life following the fish kill, any existing fish kill 5b impairment will remain in Category 5b until more recent sampling has shown recovery of the aquatic community or the responsible party has paid restitution.

Details about the 2005 fish kill can be found here: https://programs.iowadnr.gov/fishkill/Events/650

Monitoring and Methods

Assessment Key Dates

8/14/2005

Fish Kill

6/3/2020

Monitoring Start

8/23/2022

Monitoring End

Methods

120

Surveys of fish and game biologists/other professionals

140

Incidence of spills and/or fish kills

150

Monitoring data more than 5 years old

200

Physical/Chemical Monitoring

420

Indicator bacteria monitoring