2024 Pending assessment for Lime Creek

Lime Creek IA 02-CED-524

mouth (SW 1/4 S4 T86N R10W Benton Co.) to confluence with unnamed tributary in S1 T87N R10W Buchanan Co.

Assessment Cycle

2024

Release Status

Pending

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 2020 - 2022
Stream/River Water Quality Data	CY 2020 - 2022
Lake Water Quality Data	CY 2018 - 2022
Biological Sampling Data	CY 2018 - 2022*
Fish Kill Data	CY 2018 - 2022
Fish Tissue Sampling Data	CY 2018 - 2022
Continuous Dissolved Oxygen Sampling Data	CY 2018 - 2022
*Biological sites sampled in both 2017 and 2021 were also assessed.

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

Created: 11/1/2023 8:12:39 AM
Updated: 1/31/2024 2:51:55 PM

Assessment conducted in accordance with Iowa's 2024 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

High

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2014

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Special project/study

TMDL Priority

Tier III

Class BWW1

Fully Supported

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 "fully supported" based on biological sampling data and water quality monitoring 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
CRWQ	23	WQ	CY 2020-2022	99990091	Lime Creek
Iowa DNR	6	WQ	CY 2020-2022	12100002	Lime Creek-Lime Creek Park- Brandon
Iowa DNR	6	BIO	See Below	154	Lime Creek	Lime Creek Park- Brandon

Presumptive Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples per Year (2020/ 2021/2022)

2020 Geometric Mean

2021 Geometric Mean

2022 Geometric Mean

Violates Annual Geometric Mean?

# 2020 SSM violations / SSM Violations needed for impairment

# 2021 SSM violations / SSM Violations needed for impairment

# 2022 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

99990091

5/5/5

275

314

332

YES

2 / NA

4 / NA

YES

Evaluated

Not

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
12100002	6	13 / 3	7.6	8.2	7.8	0	4	NO	Mon	Full
99990091	23	13 / 3	6.7	8.5	8	0	4	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
99990091	23	Chloride	15 / 3	17.7	30	22.5	NA	0 / 0	4	NO	Mon	Full
12100002	6	Dissolved Oxygen	13 / 3	6.8	12.8	9.1	0	NA / NA	4	NO	Mon	Full
99990091	23	Dissolved Oxygen	14 / 3	7	16.4	10	0	NA / NA	4	NO	Mon	Full
12100002	6	pH	13 / 3	7.6	8.2	7.8	0	NA / NA	4	NO	Mon	Full
99990091	23	pH	13 / 3	6.7	8.5	8	0	NA / NA	4	NO	Mon	Full
99990091	23	Sulfate	15 / 3	12.8	20.3	16.5	0	NA / NA	4	NO	Mon	Full
12100002	6	Temperature	13 / 3	6.1	20.8	15.2	0	NA / NA	4	NO	Mon	Full
99990091	23	Temperature	15 / 3	5.5	27.1	18	0	NA / NA	4	NO	Mon	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
12100002	6	Ammonia	13 / 3	0.07	0.03	0.02	0 / 0	NO	Mon	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
154	9/12/22	32.5	47c	MS	Hess	68	Good	70	Fail
154	7/26/22	32.5	47c	MS	Hess	80	Excellent	70	Pass
154	7/19/21	32.5	47c	MS	Hess	80	Excellent	70	Pass
154	9/23/20	32.5	47c	MS	Hess	75	Good	70	Pass
154	7/22/19	32.5	47c	MS	Hess	72	Good	70	Pass
154	8/2/18	32.5	47c	MS	Hess	83	Excellent	70	Pass

Fish:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47c FIBI BIT	FIBI Pass/Fail
154	9/12/22	32.5	47c	MS	Yes	87	Excellent	65	Pass
154	7/19/21	32.5	47c	MS	Yes	81	Excellent	65	Pass
154	9/23/20	32.5	47c	MS	Yes	90	Excellent	65	Pass
154	7/22/19	32.5	47c	MS	Yes	90	Excellent	65	Pass
154	8/2/18	32.5	47c	MS	Yes	85	Excellent	65	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Monitored	Pass (5/6)	Full
Fish	Monitored	Pass (5/5)	Full		Assessment was monitored because the assessment
Overall	Monitored	Pass	Full	1	used multiple samples collected in the last five years.

Class BWW1- Continuous DO Monitoring:

Site ID	Data Source ID	# Days Monitoring (2021)	DO Criteria Type	# 2022 violations / Violations needed for impairment	Violates Annual Significantly >10% Rule?	Assessment Type	Support Level
			24 hr	2/25	No
12100002	6	191	16 hr	0/25	No	Evaluated	Full

Class HH – No Data

Monitoring and Methods

Assessment Key Dates

6/3/2020	Monitoring Start
7/26/2022	Biological Monitoring
7/19/2021	Biological Monitoring
8/2/2018	Biological Monitoring
7/22/2019	Biological Monitoring
9/23/2020	Biological Monitoring
9/12/2022	Biological Monitoring
10/6/2022	Monitoring End

Methods

200	Physical/Chemical Monitoring
315	Regional reference site approach
320	Benthic macroinvertebrate surveys
330	Fish surveys
420	Indicator bacteria monitoring

Water Quality Assessments

Impaired Waters List

Lime Creek IA 02-CED-524

Assessment Summary

Assessment Explanation

Assessment Key Dates

Methods