2022 Final assessment for Wolf Creek

Wolf Creek IA 02-CED-530

mouth (S29 T87N R11W Black Hawk Co.) to confluence with Twelvemile Cr. in S19 T86N R13W Tama Co.

Assessment Cycle

2022

Release Status

Final

Data Collection Period

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.

Overall IR Category: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown

Created: 12/22/2021 12:40:38 PM
Updated: 1/13/2022 9:31:33 AM

Assessment conducted in accordance with Iowa's 2022 IR methodology

Use Support

Class A1

Presumptive Use

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not Supported

Impairment Code

5p - Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2008

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Ambient monitoring: Iowa DNR-rivers

TMDL Priority

Tier III

Class BWW1

WINOFI

Biological: low aquatic macroinvertebrate IBI

Support Level

Water in Need of Further Investigation (WINOFI)

Impairment Code

3b-c - Use potentially biologically impaired based on calibrated IBI metrics.

Cause Magnitude

Slight

Status

New

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2022

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

Class HH

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use was assessed as "not supported" due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class BWW1 use was assessed as "WINOFI" 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	WQ	CY 2018-2020	10070002	Wolf Creek at La Porte City
CRWQ	23	WQ	CY 2018-2020	99990048	Wolf Creek
Iowa DNR	6	BIO	See Below	1262	Wolf Creek	LaPorte City – REMAP #402
Iowa DNR	6	BIO	See Below	1154	Wolf Creek	Main St Bridge – LaPorte City

Presumptive Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples per Year (2018/ 2019/2020)

2018 Geometric Mean

2019 Geometric Mean

2020 Geometric Mean

Violates Annual Geometric Mean?

# 2018 SSM violations / SSM Violations needed for impairment

# 2019 SSM violations / SSM Violations needed for impairment

# 2020 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

10070002

6/8/8

492

414

146

YES

4 / NA

5 / 3

3 / 3

YES

Monitored

Not

99990048

5/5/5

836

511

513

YES

5 / NA

4 / NA

3 / NA

Evaluated

Not

Class A - 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
10070002	6	36 / 3	7	8.4	8.1	0	7	NO	Monitored	Full
99990048	23	13 / 3	6.72	8.27	7.89	0	4	NO	Monitored	Full

Class BWW1 - Conventional 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
10070002	6	Ammonia	36 / 3	0.02	0.26	0.04	NA	0 / 0	7	NO	Monitored	Full
10070002	6	Chloride	36 / 3	15	24	18	NA	0 / 0	7	NO	Monitored	Full
99990048	23	Chloride	15 / 3	8.8	26.4	17.3	NA	0 / 0	4	NO	Monitored	Full
10070002	6	Dissolved Oxygen	36 / 3	7.7	13.7	10.5	0	NA / NA	7	NO	Monitored	Full
99990048	23	Dissolved Oxygen	14 / 3	5.9	11.6	8	0	NA / NA	4	NO	Monitored	Full
10070002	6	pH	36 / 3	7	8.4	8.1	0	NA / NA	7	NO	Monitored	Full
99990048	23	pH	13 / 3	6.72	8.27	7.89	0	NA / NA	4	NO	Monitored	Full
10070002	6	Sulfate	36 / 3	11	43	21	0	NA / NA	7	NO	Monitored	Full
99990048	23	Sulfate	15 / 3	8.5	39.8	21.1	0	NA / NA	4	NO	Monitored	Full
10070002	6	Temperature	36 / 3	0.2	25.5	11.6	0	NA / NA	7	NO	Monitored	Full
99990048	23	Temperature	15 / 3	9.6	23.9	18.9	0	NA / NA	4	NO	Monitored	Full

Class BWW1 - Toxic Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Acute / Chronic Violations	>1 Acute / Chronic Violation	Assessment Type	Support Level
10070002	6	Aluminum	14 / 3	4.1	1.3	0.7	0 / 0	NO	Monitored	Full
10070002	6	Arsenic	13 / 3	1.2	0.7	0.7	0 / 0	NO	Monitored	Full
10070002	6	Cadmium	13 / 3	0.07	0.03	0.02	0 / 0	NO	Monitored	Full
10070002	6	Chromium	13 / 3	1.2	0.8	0.8	0 / 0	NO	Monitored	Full
10070002	6	Lead	13 / 3	0.25	0.11	0.08	0 / 0	NO	Monitored	Full
10070002	6	Nickel	13 / 3	2.9	2.2	2.3	0 / 0	NO	Monitored	Full
10070002	6	Silver	13 / 3	0.025	0.025	0.025	0 / 0	NO	Monitored	Full
10070002	6	Zinc	13 / 3	4.4	2	1.8	0 / 0	NO	Monitored	Full

Class BWW1 - Biological Sampling:

Benthic Macroinvertebrates:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	BM Sample Gear	BMIBI score	BMIBI Class	47c BMIBI BIT	BMIBI Pass/ Fail
1262	8/25/20	306	47c	MS	Floating Art Sub	49	Fair	52	Fail
1154	8/15/18	326	47c	MS	Floating Art Sub	81	Excellent	52	Pass

Fish:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47c FIBI BIT	FIBI Pass/ Fail
1262	8/25/20	306	47c	MS	No	61	Good	44	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (1/2)	Not
Fish	Evaluated	Pass (1/1)	Full	3bc	Assessment was evaluated because although the BMIBI assessment used
Overall	Evaluated	Fail	WINOFI		multiple samples collected in the last five years, it was inconclusive.

Class HH – No Data

Monitoring and Methods

Assessment Key Dates

8/15/2018	Biological Monitoring
1/8/2018	Fixed Monitoring Start Date
12/7/2020	Fixed Monitoring End Date
8/25/2020	Biological Monitoring

Methods

230	Fixed station physical/chemical (conventional plus toxic pollutants)
315	Regional reference site approach
320	Benthic macroinvertebrate surveys
380	Quantitative physical habitat assessment
420	Indicator bacteria monitoring

Water Quality Assessments

Impaired Waters List

Wolf Creek IA 02-CED-530

Assessment Summary

Assessment Explanation

Assessment Key Dates

Methods