Brush Creek IA 01-VOL-318

from confluence with Bear Cr. (S8 T92N R7W Fayette Co.) to east line of S17 T92N R7W 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
View assessment methodology in new window

Cycle: 2024
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 11/1/2023 8:12:38 AM
Updated: 12/15/2023 8:14:27 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class A2

Recreation - Secondary contact

Not Assessed

Class BCW1

Aquatic Life - Cold Water Type 1

Not Supported

Biological: low aquatic macroinvertebrate IBI

Support Level

Not Supported

Impairment Code

5b-v - Biological - verified

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2006

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

TMDL Priority

Tier IV

Class HH

Human Health -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class BCW1 use was assessed as "not supported" based on biological sampling data. All other designated uses were "not assessed." The biological sampling site is approximately 1/10th of a mile from the upper end of the cold water segment. At this time, DNR does not know if the spring is above or below the sampling site and if the biological sampling data should be judged on a cold or warm water basis.

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	406	Brush Creek	Arlington

Presumptive Class A1 - No Data

Class A2 - No Data

Class BCW1 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/ Thermal	BM Sample Gear	CBI score	CBI Class	CBI BIT	CBI Pass/ Fail
406	8/11/14	11	52b	MS/CW	Hess	40	NA	60	Fail
406	9/16/13	11	52b	MS/CW	Hess	47	NA	60	Fail

Overall BCW1 Assessment:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (0/2)	Not	5bv	Assessment was evaluated because the assessment used sample(s) collected more than five years ago.

Hypothetical WW Biological Assessment:

Class BWW2 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/ Thermal	BM Sample Gear	BMIBI score	BMIBI Class	52b BMIBI BIT	BMIBI Pass/ Fail
406	8/11/14	11	52b	MS/WW	Hess	76	Excellent	61	Pass
406	9/16/13	11	52b	MS/WW	Hess	75	Good	61	Pass

Fish:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/ Thermal	Riffle Site?	FIBI score	FIBI Class	52b FIBI BIT	FIBI Pass/ Fail
406	8/11/14	11	52b	MS/WW	NA	86	Excellent	52	Pass
406	9/16/13	11	52b	MS/WW	NA	79	Excellent	52	Pass

Overall Hypothetical BWW2 Assessment:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Pass (2/2)	Full
Fish	Evaluated	Pass (2/2)	Full
Overall	Evaluated	Pass	Full	1	Assessment was evaluated because the assessment used sample(s) collected more than five years ago.

Class HH – No Data

Monitoring and Methods

Assessment Key Dates

9/16/2013

Biological Monitoring

8/11/2014

Biological Monitoring

Methods

150

Monitoring data more than 5 years old

315

Regional reference site approach

320

Benthic macroinvertebrate surveys