Bass Creek IA 01-TRK-216

west line of S3 T95N R9W (Fayette Co.) to confuence with unnamed tributary in S4 T95N R9W Fayette 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: 1/9/2024 10:56:54 AM
Updated: 1/29/2024 2:18:18 PM

Use Support

Class A1

Presumptive Use

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

New

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2024

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Ambient monitoring: Iowa DNR-rivers

TMDL Priority

Tier III

Class BWW2

Aquatic Life - Warm Water Type 2

Fully Supported

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use was assessed as "not supported" due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class BWW2 use was assessed as “fully supported” based on a DNR Fisheries Bureau summary on trout reproduction and on water quality monitoring data. Although not designated for the coldwater aquatic life use in the Iowa Water Quality Standards, part of this segment is identified as a trout stream by the DNR Fisheries Bureau.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2021-2022	14000344	Bass Creek

Presumptive Class A1 - Indicator Bacteria:

Site ID	Data Source ID	# Samples per Year (2021/2022)	2021 Geometric Mean	2022 Geometric Mean	Violates Annual Geometric Mean?	# 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
14000344	6	2/7	614	768	YES	2 / NA	5 / 3	YES	Mon	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
14000344	6	10 / 2	7.71	8.31	7.94	0	3	NO	Mon	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
14000344	6	Dissolved Oxygen	10 / 2	8.07	13.81	10.17	0	NA / NA	3	NO	Mon	Full
14000344	6	pH	10 / 2	7.71	8.31	7.94	0	NA / NA	3	NO	Mon	Full
14000344	6	Temperature	10 / 2	2.4	20.1	12.7	0	NA / NA	3	NO	Mon	Full

Class BWW2 - Natural Trout Reproduction:

Even though Bass Creek is classified as a BWW2 stream, based on the January 2024 trout reproduction in Iowa streams summary prepared by the DNR Fisheries Bureau, the Class BWW2 aquatic life use of Bass Creek was assessed as "fully supported." According to the updated summary, this stream was placed in Category II: streams that exhibit recent but inconsistent reproductive success and occasional stocking may be needed to maintain the trout population.

Monitoring and Methods

Assessment Key Dates

1/1/2024

Biological Monitoring

5/20/2021

Monitoring Start

11/15/2022

Monitoring End

Methods

120

Surveys of fish and game biologists/other professionals

200

Physical/Chemical Monitoring

420

Indicator bacteria monitoring