Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Ashton Creek IA 06-LSR-2048

from tributary(T89N R41W Sec3 Ida Co.) to headwaters (T88N R41W Sec2) Ida Co.

Cycle
2024
Release Status
Final
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
11/1/2023 8:13:28 AM
Updated
12/28/2023 11:06:41 AM
Use Support
Class A1
Recreation - Primary contact
Fully Supported
Class BWW1
Aquatic Life - Warm Water Type 1
WINOFI
Impairment Code
3b-u - Use potentially biologically impaired based on uncalibrated IBI metrics.
Cause Magnitude
Moderate
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
Low
Cycle Added
2008
Impairment Rationale
Low Biotic Index
Data Source
Biological monitoring: Iowa DNR WQMA
Impairment Delistings
Cycle Added Class Cause Data Source Rationale
2010 Class BWW1 Organic Enrichment: Low Dissolved Oxygen Ambient monitoring: Iowa DNR-rivers New data: WQ improvement (chemical / physical / bacterial)
Documentation
Assessment Summary

The presumptive Class A1 use was assessed as “fully supported” based on pH sampling data. The presumptive Class BWW1 use was assessed as “WINOFI” based on biological sampling data.

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

16470003

Ashton Creek - Site 209

Iowa DNR

6

BIO

See Below

603

Ashton Creek

Washta (REMAP #209)


Presumptive Class A1 - Indicator Bacteria: No Data


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

16470003

6

10 / 2

7.26

7.87

7.64

0

3

NO

Mon

Full


Class BWW1 - 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

16470003

6

Dissolved Oxygen

10 / 2

4.4

10.5

7.4

1

NA / NA

3

NO

Mon

Full

16470003

6

pH

10 / 2

7.26

7.87

7.64

0

NA / NA

3

NO

Mon

Full

16470003

6

Temperature

10 / 2

4.34

18.36

14.39

0

NA / NA

3

NO

Mon

Full


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

47a BMIBI BIT

BMIBI Pass/Fail

603

7/7/06

6.5

47a

MO/WW

ArtSub

20

Poor

51

Fail

603

7/7/06

6.5

47a

MO/WW

Surber

26

Poor

51

Fail


Fish:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/Thermal

Riffle Stream?

FIBI score

FIBI Class

47a FIBI BIT

FIBI Pass/Fail

603

7/7/06

6.5

47a

MO/WW

NA

1

Poor

43

Fail


Overall:

Community

Assessment Type

Assessment Result

Support Level

IR Category

Reason

Benthic Macroinvertebrates

Evaluated

Fail (0/2)

WINOFI

Fish

Evaluated

Fail (0/1)

WINOFI

Assessment was evaluated because it was based on a single year and

Overall

Evaluated

Fail

WINOFI

3bu

the drainage area of the site was smaller than the calibrated range.



Monitoring and Methods
Assessment Key Dates
7/6/2006
Biological Monitoring
6/10/2021
Monitoring Start
10/13/2022
Monitoring End
Methods
150
Monitoring data more than 5 years old
200
Physical/Chemical Monitoring
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys