2022 Final assessment for Beaver Creek

Beaver Creek IA 02-CED-555

mouth (S34 T90N R14W Black Hawk Co.) to confluence with South Beaver Cr. in S25 T90R R17W Butler 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 1:17:43 PM
Updated: 1/28/2022 1:24:51 PM

Assessment conducted in accordance with Iowa's 2022 IR methodology

Use Support

Class A2

WINOFI

Bacteria: Indicator Bacteria- E. coli

Support Level

Water in Need of Further Investigation (WINOFI)

Impairment Code

3b - Use potentially impaired based on an evaluated assessment.

Cause Magnitude

Moderate

Status

New

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2022

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Watershed project monitoring

Class A3

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

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

Fully Supported

Class HH

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A2 use was assessed as "WINOFI due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class A3 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 ambient water quality monitoring data and 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	10070001	Beaver Creek near Cedar Falls
CRWQ	23	WQ	CY 2018-2020	99990069	Beaver Creek
CRWQ	23	WQ	CY 2018-2020	99990074	Beaver Creek
CRWQ	23	WQ	CY 2018-2020	99990075	Beaver Creek
Iowa DNR	6	BIO	See Below	373	Beaver Creek	New Hartford – REMAP #76
Iowa DNR	6	BIO	See Below	947	Beaver Creek	Cedar Falls

Class A2 - 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

10070001

7/8/8

573

430

130

0 / 3

Monitored

WINOFI

99990069

5/5/5

443

255

237

0 / NA

Evaluated

WINOFI

99990074

5/5/5

700

485

346

YES

0 / NA

Evaluated

WINOFI

99990075

5/5/5

1133

385

267

YES

0 / NA

Evaluated

WINOFI

Class A3 - 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

10070001

7/8/8

573

430

130

YES

6 / 3

5 / 3

2 / 3

YES

Monitored

Not

99990069

5/5/5

443

255

237

YES

4 / NA

2 / NA

3 / NA

Evaluated

Not

99990074

5/5/5

700

485

346

YES

3 / NA

5 / NA

4 / NA

Evaluated

Not

99990075

5/5/5

1133

385

267

YES

4 / NA

2 / 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
10070001	6	36 / 3	7.1	8.4	8.1	0	7	NO	Monitored	Full
99990069	23	14 / 3	7.73	8.53	8.11	0	4	NO	Monitored	Full
99990074	23	14 / 3	7.9	8.5	8.1	0	4	NO	Monitored	Full
99990075	23	14 / 3	7.75	8.36	8.12	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
10070001	6	Ammonia	36 / 3	0.02	0.37	0.04	NA	0 / 0	7	NO	Monitored	Full
10070001	6	Chloride	36 / 3	14	22	18	NA	0 / 0	7	NO	Monitored	Full
99990069	23	Chloride	15 / 3	14.3	20.3	16.6	NA	0 / 0	4	NO	Monitored	Full
99990074	23	Chloride	15 / 3	14.3	21.5	17.3	NA	0 / 0	4	NO	Monitored	Full
99990075	23	Chloride	15 / 3	14.4	21.9	17.3	NA	0 / 0	4	NO	Monitored	Full
10070001	6	Dissolved Oxygen	36 / 3	7.5	13.5	10.2	0	NA / NA	7	NO	Monitored	Full
99990069	23	Dissolved Oxygen	15 / 3	6.1	10.8	8.2	0	NA / NA	4	NO	Monitored	Full
99990074	23	Dissolved Oxygen	15 / 3	6	11.1	8.1	0	NA / NA	4	NO	Monitored	Full
99990075	23	Dissolved Oxygen	15 / 3	5.6	10.8	8.1	0	NA / NA	4	NO	Monitored	Full
10070001	6	pH	36 / 3	7.1	8.4	8.1	0	NA / NA	7	NO	Monitored	Full
99990069	23	pH	14 / 3	7.73	8.53	8.11	0	NA / NA	4	NO	Monitored	Full
99990074	23	pH	14 / 3	7.9	8.5	8.1	0	NA / NA	4	NO	Monitored	Full
99990075	23	pH	14 / 3	7.75	8.36	8.12	0	NA / NA	4	NO	Monitored	Full
10070001	6	Sulfate	36 / 3	11	29	19	0	NA / NA	7	NO	Monitored	Full
99990069	23	Sulfate	15 / 3	10.5	25.1	18.2	0	NA / NA	4	NO	Monitored	Full
99990074	23	Sulfate	15 / 3	11.9	27.1	19	0	NA / NA	4	NO	Monitored	Full
99990075	23	Sulfate	15 / 3	12.2	25.8	18.7	0	NA / NA	4	NO	Monitored	Full
10070001	6	Temperature	36 / 3	0.1	25.9	11.2	0	NA / NA	7	NO	Monitored	Full
99990069	23	Temperature	15 / 3	9.1	24.1	19.3	0	NA / NA	4	NO	Monitored	Full
99990074	23	Temperature	15 / 3	8.5	23.8	19.1	0	NA / NA	4	NO	Monitored	Full
99990075	23	Temperature	15 / 3	8.1	24.3	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
10070001	6	Aluminum	14 / 3	5.5	1	0.6	0 / 0	NO	Monitored	Full
10070001	6	Arsenic	13 / 3	1.3	0.8	0.8	0 / 0	NO	Monitored	Full
10070001	6	Cadmium	13 / 3	0.06	0.03	0.02	0 / 0	NO	Monitored	Full
10070001	6	Chromium	13 / 3	1.2	0.8	0.9	0 / 0	NO	Monitored	Full
10070001	6	Lead	13 / 3	0.2	0.1	0.1	0 / 0	NO	Monitored	Full
10070001	6	Nickel	13 / 3	3.1	2.3	2.3	0 / 0	NO	Monitored	Full
10070001	6	Silver	13 / 3	0.025	0.025	0.025	0 / 0	NO	Monitored	Full
10070001	6	Zinc	13 / 3	3.2	1.9	2.1	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
373	8/25/20	375	47c	MS	Art Sub	73	Good	52	Pass
947	8/19/19	391	47c	MS	Art Sub	70	Good	52	Pass

Fish:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47c FIBI BIT	FIBI Pass/ Fail
373	8/25/20	375	47c	MS	No	58	Good	44	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Monitored	Pass (2/2)	Full
Fish	Evaluated	Pass (1/1)	Full	1	Assessment was monitored because the BMIBI assessment used multiple
Overall	Monitored	Pass	Full		samples collected in the last five years.

Class BWW1 - Continuous DO Monitoring:

Site ID	Data Source ID	# Days Monitoring (2016/2017/2018/ 2019/2020)	DO Criteria Type	# 2016 violations / Violations needed for impairment	# 2017 violations / Violations needed for impairment	# 2018 violations / Violations needed for impairment	# 2019 violations / Violations needed for impairment	# 2020 violations / Violations needed for impairment	Violates Annual Significantly >10% Rule?	Assessment Type	Support Level
			24 hr	NA	NA	NA	NA	0/4	No
373	6	0/0/0/0/15	16 hr	NA	NA	NA	NA	0/4	No	Evaluated	Full

Class HH – No Data

Monitoring and Methods

Assessment Key Dates

1/8/2018	Fixed Monitoring Start Date
12/7/2020	Fixed Monitoring End Date
8/25/2020	Biological Monitoring
8/19/2019	Biological Monitoring
5/17/2018	Non-fixed Monitoring Start Date
9/28/2020	Non-fixed Monitoring End Date

Methods

220	Non-fixed station physical/chemical monitoring (conventional pollutant only)
230	Fixed station physical/chemical (conventional plus toxic pollutants)
315	Regional reference site approach
320	Benthic macroinvertebrate surveys
330	Fish surveys
380	Quantitative physical habitat assessment
420	Indicator bacteria monitoring

Water Quality Assessments

Impaired Waters List

Beaver Creek IA 02-CED-555

Assessment Summary

Assessment Explanation

Assessment Key Dates

Methods