2020 assessment for Mill Creek

Mill Creek IA 01-TRK-6500

from mouth (T91N R3W Sec11) to headwaters (T91N R3W Sec23)

2020
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
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Overall IR

2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.

Trend

Unknown

Created

9/28/2020 10:01:51 AM by

Updated

10/12/2020 7:51:50 AM by

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW1

Presumptive Use

Aquatic Life - Warm Water Type 1

Fully Supported

General Use

General Use water -

Not Assessed

303(d) Delistings for this Cycle

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class BWW1 use was assessed as “fully supported” based on biological sampling data. 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	862	Mill Creek	Osterdock – PeCr4

Presumptive Class BWW1 - 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
862	9/6/11	3	52b	MS/WW	Hess	70	Good	61	Pass
862	7/25/11	3	52b	MS/WW	Hess	78	Excellent	61	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	Earned IR Category	Actual IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Pass (2/2)	Full	1	1	Assessment was evaluated because the drainage area of the sample site was smaller than the calibrated range.

Monitoring and Methods

Assessment Key Dates

7/25/2011

Biological Monitoring

9/6/2011

Biological Monitoring

Methods

150

Monitoring data more than 5 years old

315

Regional reference site approach

320

Benthic macroinvertebrate surveys