Mill Creek IA 06-LSR-1615

mouth (S14 T92N R40W Cherokee Co.) to confluence with Whisky Cr. at east line S29 T94N R41W O'Brien 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: 12/3/2021 6:58:47 AM
Updated: 1/25/2022 4:03:42 PM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW2

Aquatic Life - Warm Water Type 2

Not Supported

Biological: low fish & invert IBIs- cause unknown

Support Level

Not Supported

Impairment Code

5b-v - Biological - verified

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2004

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

TMDL Priority

Tier IV

Fish Kill: Caused By Animal Waste

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

High

Status

Continuing

Source

Agriculture: Animal Feeding Operations

Source Confidence

High

Cycle Added

2018

Impairment Rationale

Pollutant-caused fish kill

Data Source

Fish kill investigation: Iowa DNR

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class BWW2 use was assessed as “not supported” based on biological sampling data and on a fish kill investigation. All other designated uses were "not assessed."

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	1203	Mill Creek	NE of Meriden – REMAP #436
Iowa DNR	6	BIO	See Below	142	Mill Creek	Larrabee

Presumptive Class A1 – No Data

Class BWW2 - Biological Sampling:

Benthic Macroinvertebrates:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	BM Sample Gear	BMIBI score	BMIBI Class	47a BMIBI BIT	BMIBI Pass/Fail
1203	9/17/19	267	47a	MO	Hess	54	Fair	54	Pass
142	9/19/17	259	47a	MO	ArtSub	47	Fair	54	Fail
142	8/1/16	259	47a	MO	ArtSub	45	Fair	54	Fail

Fish:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47a FIBI BIT	FIBI Pass/Fail
1203	9/17/19	267	47a	MO	NA	28	Fair	43	Fail
142	9/19/17	259	47a	MO	NA	39	Fair	43	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Monitored	Fail (1/3)	Not		Assessment was monitored because the samples used to complete the
Fish	Monitored	Fail (0/2)	Not	5bv	assessment were collected in the last five years.
Overall	Monitored	Fail	Not

Class BWW2 – Fish kill Assessment:

The Class BWW2 aquatic life use previously resided in Category 4d based on the assessment developed for the 2013 fish kill. Because no additional fish kills were reported in this segment for at least five years post fish kill (2018), the Category for the fish kill assessment was changed from 4d to 3b (potentially impaired). DNR believes that any impact from the fish kill from which the impairment was based has likely dissipated. If no additional fish kills are reported in the segment for an additional five-year period (2023), the Category will be changed from 3b to 3a (not assessed).

Details about the 2013 fish kill can be found here: https://programs.iowadnr.gov/fishkill/Events/876

Class BWW2- Continuous DO Monitoring:

Site ID	Data Source ID	# Days Monitoring (2016/2017/2018/ 2019/2020)	DO Criteria Type	# 2016 violations / Violations needed for impairment	# 2017 violations / Violations needed for impairment	# 2018 violations / Violations needed for impairment	# 2019 violations / Violations needed for impairment	# 2020 violations / Violations needed for impairment	Violates Annual Significantly >10% Rule?	Assessment Type	Support Level
			24 hr	0/15	NA	NA	NA	NA	No
142	6	98/0/0/0/0	16 hr	0/15	NA	NA	NA	NA	No	Evaluated	Full

Monitoring and Methods

Assessment Key Dates

8/1/2016

Biological Monitoring

9/17/2019

Biological Monitoring

8/17/2013

Fish Kill

9/19/2017

Biological Monitoring

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

222

Non-fixed-station monitoring (conventional during key seasons and flows)

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

380

Quantitative physical habitat assessment