East Fork Unnamed Tributary to Arbor Lake IA 03-NSK-1874

mouth (NW1/4 SE1/4 S17 T80N R17W Poweshiek Co.) to headwaters at 1st Avenue Grinnell (T80 R16W Sec17 Poweshiek 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 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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Cycle: 2020
Release Status: Final
Overall IR: 3 - Insufficient data exist to determine whether any designated uses are met.
Trend: Unknown
Created: 9/23/2020 12:34:15 PM
Updated: 10/14/2020 7:50:55 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW1

Presumptive Use

Aquatic Life - Warm Water Type 1

WINOFI

Biological: low fish IBI

Support Level

Further Investigation Needed

Impairment Code

3b-u - Use potentially biologically impaired based on uncalibrated IBI metrics.

Cause Magnitude

High

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2006

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class BWW1 use was assessed as “not supported” based on biological sampling data. All other designated uses were "not assessed".

Assessment Explanation

Sources of Data:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	BIO	See Below	383	East Fork Unnamed Tributary to Arbor Lake	Grinnell

Presumptive Class A1 - No Data

Presumptive Class BWW1 - Biological Sampling:

Fish:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/ Thermal	Riffle Stream?	FIBI score	FIBI Class	47f FIBI BIT	FIBI Pass/ Fail
383	10/10/03	0.3	47f	MS/WW	NA	0	Poor	36	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	Earned IR Category	Actual IR Category	Reason
Fish	Evaluated	Fail (0/1)	Not	3bu	3bu	Assessment is evaluated because the drainage area of the sample site was smaller than the calibrated range.

Monitoring and Methods

Assessment Key Dates

10/10/2003

Biological Monitoring

Methods

150

Monitoring data more than 5 years old

315

Regional reference site approach

330

Fish surveys